JP2000353858A - Surface emitting laser and manufacturing method thereof - Google Patents

Abstract

(57) [Problem] To provide a surface emitting laser which can oscillate in a long wavelength band, can operate in a single transverse mode, is thin, has high reliability, and is easy to manufacture. SOLUTION: An active layer 11 and an upper multilayer semiconductor layer 26 of a semiconductor layer 24 / semiconductor layer 25 and a lower multilayer semiconductor layer 5 of a semiconductor layer 3 / semiconductor layer 4 are provided above and below a structure formed by burying the active layer in a semiconductor. . The upper multilayer semiconductor layer 26 is removed from the semiconductor layer 24 to the optical waveguide portion while leaving a part of the semiconductor layer / semiconductor layer, and the lower multilayer semiconductor layer 5 is also guided to the semiconductor layer 3 while leaving a part of the semiconductor layer / semiconductor layer. The air layer 24a / semiconductor layer 25DBR structure and the air layer 3a / semiconductor layer 4 have a DBR structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surface emitting laser and a method for manufacturing the same.

[0002]

2. Description of the Related Art Since a surface emitting laser is easy to form a two-dimensional array, and has a small emission angle and is a circular beam, it is advantageous for coupling with a fiber. Promising as a light source for processing. Further, since the surface emitting laser can reduce the threshold value by miniaturization, it is also expected to have low power consumption.
At present, only the surface-emitting laser with an output wavelength of 0.85 μm or 0.98 μm manufactured on a GaAs substrate has been practically used.

A long-wavelength surface emitting laser having an output wavelength of 1.3 μm or 1.55 μm is promising for long-distance transmission and further lowering the threshold. Conventionally, AlGaAs grown on a GaAs substrate
Bragg reflector and GaInA grown on InP substrate
With the configuration in which the active layer of sP was bonded, continuous oscillation at room temperature was possible. However, it is not yet practical in terms of output and reliability. In addition, in the surface emitting laser by the conventional method, the bonding interface is not sufficient in conductivity or light absorption, the light absorption there is large because the reflecting mirror is thick, and the GaInAsP active layer is used to confine carriers and absorb light. And the like, which is insufficient in that the temperature characteristics are not good, and the like, and a manufacturing defect that a complicated manufacturing process by bonding easily deteriorates the yield.

Hereinafter, a distributed Bragg reflector is referred to as a DBR (Disable).
tributed Bragg Reflector).

In the configuration of the long-wavelength band surface emitting laser,
A structure having an air / semiconductor DBR (distributed Bragg reflector), which has high reflectivity, enables high-precision wavelength control of a grown film, and is easy to fabricate, has been reported ("ELEC").
TRONICS LETTERS, 18th July1996, Vol.32, No.15, 136
9-1370 "). However, in the configuration of this report, it is impossible to uniformly inject current into the active layer, so that only the photoexcitation is achieved.

Here, the notation "X layer / Y layer" means a structure in which X layers and Y layers are alternately stacked.

[0007] As for a GaAs-based short-wavelength surface emitting laser, a structure using an AlAs oxide layer / GaAs DBR (distributed Bragg reflector) has been reported (IEEE PHOTO).
NICS TECHNOLOGY LETTERS, Vol.7, No.9, SEPTEMBER 19
95, 968-970 "). However, in the configuration reported in this report, the active layer does not have an optical waveguide structure, so that the transverse mode tends to be multi-mode at high output, and current cannot flow through the upper and lower DBRs. There is a drawback that the structure is difficult to produce because the electrodes are formed in layers, and that the lower DBR is also a semiconductor / oxide, so that the heat release is poor. All DBRs are semiconductor /
Since the semiconductor is changed to a semiconductor / oxide by steam oxidation, there is a disadvantage that the film thickness changes. Furthermore,
It is difficult to obtain a surface emitting laser in a long wavelength band with the configuration of this report.

In a current injection type surface emitting laser in a long wavelength band,
There is no report that a semiconductor / air or semiconductor / oxide DBR was formed using a lattice-matched crystal film.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, an object of the present invention is to provide a surface emitting laser having any of the following features and a method of manufacturing the same. (1) In order to obtain high reflectance with a small number of pairs,
The difference in the refractive index between the films constituting the film must be large. (2) To be able to be manufactured by a vapor phase epitaxy method with excellent controllability so that highly accurate wavelength control is possible. (3) The film thickness is smaller than that having a semiconductor / semiconductor DBR. (4) A structure capable of injecting current through a DBR so that fabrication is easy. (5) The active layer has an optical waveguide structure so that single transverse mode operation is possible. (6) Part of the lower DBR is semiconductor / semiconductor for good heat release. (7) The semiconductor / semiconductor remains in a part of the DBR so that the film thickness of the semiconductor / oxide does not change due to steam oxidation. (8) Able to oscillate in the long wavelength band. (9) It must be easy to manufacture, have good reliability, and be capable of continuous growth under lattice-matching conditions so as to obtain high characteristics.

[0010]

According to a first aspect of the present invention, there is provided a surface emitting laser according to the first aspect of the present invention, wherein a first semiconductor layer is formed above and below an active layer and a structure in which the active layer is embedded in a semiconductor. And a conductive lower multilayer semiconductor layer in which a first semiconductor layer and a second semiconductor layer are alternately laminated. And having an electrode layer on the upper multilayer semiconductor layer,
The upper multilayer semiconductor layer has a distributed Bragg reflector structure in which a first semiconductor layer in a region including immediately above the active layer is removed, and an air layer and a second semiconductor layer are alternately stacked. And the lower multilayer semiconductor layer is a distributed Bragg reflector structure in which the first semiconductor layer in a region including immediately below the active layer is removed, and an air layer and a second semiconductor layer are alternately stacked. It is characterized by becoming.

According to a second aspect of the present invention, there is provided a surface emitting laser, comprising: an active layer and a structure in which the active layer is buried in a semiconductor;
A conductive upper multilayer semiconductor layer in which first semiconductor layers and second semiconductor layers are alternately stacked, and a conductive lower multilayer in which first semiconductor layers and second semiconductor layers are alternately stacked. A semiconductor layer, having an electrode layer on the upper multilayer semiconductor layer, wherein the upper multilayer semiconductor layer is formed by oxidizing a first semiconductor layer in a region including immediately above the active layer; A distributed Bragg reflector structure in which two semiconductor layers are alternately stacked, and the first semiconductor layer in a region including the lower multilayer semiconductor layer immediately below the active layer is oxidized, A distributed Bragg reflector structure in which an oxide layer and a second semiconductor layer are alternately stacked is characterized.

According to a third aspect of the present invention, in the surface emitting laser, the first semiconductor layer of the upper multilayer semiconductor layer is formed of AlGaInAs.
Wherein the second semiconductor layer is AlGaInP; and
The first semiconductor layer of the lower multilayer semiconductor layer is AlGaInAs and the second semiconductor layer is AlGaInP,
The surface emitting laser according to the invention according to claim 4, wherein the structure in which the semiconductor is buried around the active layer has a refractive index waveguide structure in which the average refractive index of the buried portion is higher than the average refractive index of the buried layer. The surface emitting laser according to the invention according to claim 5, wherein the buried layers are p-type AlGaInAsP and n-type AlGaInAsP.
Repeated layer, semi-insulating A doped with Fe or Cr
The surface emitting laser according to the invention according to claim 6, characterized in that it has an lGaInAsP layer or an oxide layer of AlGaInAs having a higher Al composition than other buried layers between these layers.
A buried portion including the active layer having a structure in which the semiconductor is buried around the active layer is made of AlGaInAs, and has a distributed Bragg reflector structure with low reflectance above and below it.

Further, the invention according to claim 7 is a method for manufacturing a surface emitting laser having a distributed Bragg reflector structure in which air layers and second semiconductor layers are alternately stacked, and wherein the vertical distribution Type Bragg reflector structure, AlGaInAs layer and Al
Al of the upper and lower multilayer semiconductor layers alternately laminated with GaInP layers
It is characterized in that only the GaInAs layer is selectively etched up to the optical waveguide portion.

An eighth aspect of the present invention is a method of manufacturing a surface emitting laser having a distributed Bragg reflector structure in which oxide layers and second semiconductor layers are alternately stacked, and the upper and lower distributed Bragg reflector structures. Bragg reflector structure, AlGaInAs layer and AlGaIn
AlGaIn of upper and lower multilayer semiconductor layers alternately stacked with P layers
It is characterized in that only the As layer is formed by increasing the Al composition and selectively oxidizing the optical waveguide portion.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of the present invention will be described with reference to FIGS. 1 and 2 are a sectional view and a plan view showing the structure of the surface emitting laser according to the first embodiment, and FIGS. 3 to 5 show the manufacturing steps.

The surface emitting laser shown in FIGS. 1 and 2 has an active layer 11 and a structure in which the active layer 11 is buried in a semiconductor.
It has a lower multilayer semiconductor layer 5 and an upper multilayer semiconductor layer 26. An n-type electrode layer 30 is provided on the upper multilayer semiconductor layer 26, and a p-type electrode 31 is provided on the back surface of the substrate. Symbol 28 is
A protection film such as a SiO ₂ film or a SiN _X film is shown, and reference numeral 28a indicates a light emission window.

The lower multi-layer semiconductor layer 5 has a conductive multi-layer structure in which first semiconductor layers 3 and second semiconductor layers 4 are alternately stacked. Of the first semiconductor layer 3 in a region including immediately below the active layer 11 so as to leave the semiconductor layer 4 of a distributed Bragg layer in which the air layer 3a and the second semiconductor layer 4 are alternately stacked. Reflector (D
(BR) structure. Usually, the first semiconductor layer 3 is made of Al
The GaInAs layer and the second semiconductor layer 4 are AlGaInP layers.
The DBR structure is formed by selectively etching only the InAs layer 3 up to the optical waveguide portion except for a part.

The upper multi-layer semiconductor layer 26 is the first semiconductor layer 2
4 and a second semiconductor layer 25 are alternately stacked, and have a conductive multilayer film structure. The first semiconductor layer 24 and the second semiconductor layer 25 are directly over the active layer 11 so that the first semiconductor layer 24 and the second semiconductor layer 25 are partially left. The first semiconductor layer 24 in the region including the air layer 24a is removed.
And a second semiconductor layer 25 are alternately stacked to form a DBR structure. Usually, the first semiconductor layer 24 is made of AlGaInAs
The second semiconductor layer 25 is an AlGaInP layer,
The DBR structure is formed by selectively etching only the layer 24 up to the optical waveguide portion.

The structure in which the semiconductor is buried around the active layer 11 has a refractive index optical waveguide structure in which the average refractive index of the buried portion is higher than the average refractive index of the buried layer. Specifically, the average refractive index of the active layer 11 and the upper and lower multilayer films 9 and 15 is made higher than the average refractive index of the buried layer 17a, so that the active layer 11 has an optical waveguide structure.

The buried layer 17a is basically a p-type AlGaInAsP
And an n-type AlGaInAsP repetition layer, and further, an AlGaInAs oxide layer 29 having an Al composition higher than the other layers between these layers.
have.

Further, the buried portion including the active layer 11 having the structure in which the semiconductor is buried around the active layer 11 is made of AlGaIn.
It is composed of As, and has multilayer films 9 and 15 having a distributed Bragg reflector structure with low reflectivity above and below it.

The surface emitting lasers shown in FIGS. 1 and 2 have the following functions and effects. (1) Since the distributed Bragg reflector (DBR) is the air layer 3a / the second semiconductor layer 4 (or the air layer 24a / the second semiconductor layer 25), the refractive index difference between the films constituting the DBR is increased. As a result, a high reflectance can be obtained with a small number of pairs. (2) Since a vapor phase epitaxy method or the like having excellent controllability can be applied to the formation of the DBR, highly accurate wavelength control is possible. (3) Since the number of pairs of films constituting the DBR may be small,
The thickness of the surface emitting laser is smaller than that of a semiconductor / semiconductor having a DBR. (4) Since the semiconductor / semiconductor remains in a part of the DBR, an electrode can be provided there and the current can be injected through the DBR. Therefore, it is easy to manufacture a surface emitting laser. (5) Since the active layer 11 has an optical waveguide structure while simultaneously having a buried structure, a single transverse mode operation is possible. (6) Since the semiconductor / semiconductor remains in part of the lower DBR,
Good heat release. (7) Since it can be grown on the InP substrate 1 with a lattice-matched crystal growth film, it is possible to obtain a surface-emitting laser that can oscillate in a long wavelength band and has high reliability. (8) Since the multilayer films 9 and 15 having a distributed Bragg reflector structure with low reflectivity are provided above and below the active layer 11, uniform injection of current is possible and optical waveguide characteristics are further improved. Efficiency is good because it gets better. (9) From the above, a high-performance surface-emitting laser in a single transverse mode with a low threshold current and high light output is realized. (10) The buried layer 17a is basically made of p-type AlGaInAsP and n-type Al
Since the layer is a GaInAsP repeating layer, the resistance of the buried layer around the active layer 11 is high, and current is efficiently injected into the active layer 11. Furthermore, since the AlGaInAs oxide layer 29 having a high Al composition is provided, the buried layer portion around the active layer 11 has a higher resistance, and current is more efficiently injected into the active layer 11.

Next, an example of a method for manufacturing a surface emitting laser will be described.
An explanation will be given with reference to FIGS. 3 to 5 assuming that the oscillation wavelength is λ = 1.55 μm.

As shown in FIG. 3A, the p-type InP substrate 1
Above, a p-type InP buffer layer 2, for an oscillation wavelength of λ = 1.55 μm, p of optical length λ / 4
3.5 pairs of a Ga _0.468 In _0.532 As layer 3 (first semiconductor layer) and a p-type InP layer (second semiconductor layer) 4 having an optical length (3/4) λ are repeated as pairs. The lower multilayer semiconductor layer 5 (here, the optical length λ / 4 of only the GaInAs layer 3 is calculated based on the refractive index of air, and the p-type Ga _0.468 In _0.532 As layer 3 is AlGaInAs having an Al composition of zero. Type InP layer 4 has an Al composition and
AlGaInP with zero Ga composition. ), P-type InP layer 6 having an optical length of 2λ, p-type Al _x Ga _y In _1-xy As layer 7 and p-type Al _m Ga _n In _1-mn
2.5 pairs of repetitive multilayer films 9 with As layers 8 as pairs (in this case, x> m, x + y = m + n, and both layers 7 and 8 are lattice-matched to InP. Since x> m) , Layer 7
Has a larger Al composition than the layer 8. Here, x = 0.468
, Y = 0, m = 0.2, n = 0.268. p-type Al
_x Ga _y In _1-xy As layer 7 and the p-type _{Al m Ga n In 1-mn} As layer 8
AlGaInAsP with zero P composition. ), Followed by the non-doped Al _x Ga _y In _1-xy As gradient layer 1
0 (here, x = 0.2 to 0.4, y = 0.268 to 0.068), Al _0.06 Ga _0.408 In _0.532 As well layer and Al
_0.2 Ga _0.268 In _0.532 As A spacer layer 12 including an active layer (3QWs) 11 having an optical length λ composed of a barrier layer, an n-type Al _x Ga _y In _1-xy As layer 13 and an n-type Al _m Ga _n In
A multilayer film 15 in which _1-mn As layers 14 are paired and 2.5 pairs are repeated (in this case, x> m, x + y = m + n,
Both layers 13 and 14 are lattice matched to InP. x> m
Therefore, the Al composition of the layer 13 is larger than that of the layer 14.
Here, x = 0.468, y = 0, m = 0.2, and n = 0.268. n-type Al _x Ga _y In _1-xy As layer 13 and n-type Al _m Ga
_{The n} In _1-mn As layer 14 is made of AlGaInAsP having a P composition of zero. ). On top of that, a 600 nm thick SiO ₂ layer 16 is
It was patterned into a circle or a square with a diameter of ２０20 μm.

Next, as shown in FIG. 3 (b), SiO ₂ layer 1
Etching is performed up to the p-type InP layer 6 using the mask 6 as a mask, and as shown in FIG.
7, 220 nm thick n-type InP layer 18, 220 nm thick non-doped A
The structure of the lInAs layer 19, the n-type InP layer 20 having a thickness of 220 nm, and the p-type InP layer 21 having a thickness of 220 nm was repeated twice to bury and grow around the active layer 11. Here, reference numeral 22 denotes layers 17 to 21
Represents the second structure.

The layers 17 to 21 are basically made of AlGaInAsP, but the p-type InP layer 17, the n-type InP layer 18, and the n-type InP layer 2
The 0 and p-type InP layers 21 are made of n-type or p-type AlGaInAsP.
Al composition, Ga composition and As composition of zero
The non-doped AlInAs layer 19 has the Ga composition and the P composition of AlGaInAsP set to zero. The non-doped AlInAs layer 19 has a higher Al composition than the other layers 17 to 18 and 20 to 21.

Next, as shown in FIG. 4 (a), SiO ₂ layer 1
6, the n-type InP layer 2 having an optical wavelength of 2λ is removed.
3 followed by n-type Ga having an optical length of λ / 4.
_0.468 In _0.532 As layer 24 (first semiconductor layer) and optical length (3
/ 4) 2.5 pairs of n-type InP layers (second semiconductor layers) 25 of λ were repeated as pairs to grow a conductive upper multilayer semiconductor layer 26. Here, the optical length λ / 4 of the GaInAs layer 24
Only calculated based on the refractive index of air, n-type Ga _0.468 In _0.532 As
The layer 24 is made of AlGaInAs having an Al composition of zero, and n-type InP
The layer 25 is AlGaInP in which the Al composition and the Ga composition are zero.

Next, as shown in FIG. 4 (b), SiO ₂ layer 2
7 was used as a mask, and a mesa of 50 μmφ was formed by etching the layer thickness of the surface emitting laser. At the time of this etching, a mesa was formed so as to include an active layer portion inside the mesa and to shift the active layer portion away from the center of the mesa (shifted to the left in the figure). Thereafter, as shown in FIG. 4C, SiN _X or SiO ₂ was entirely deposited as a protective film 28 by a plasma CVD method.

After the entire surface of the protective film 28 is deposited, as shown in FIG. 5A, an opening is formed by selectively etching the protective film 28 on the mesa end near the active layer (left side in the figure). did.

After the opening is formed, as shown in FIG. 5B, only the n-type GaInAs layer 24 of the upper multilayer semiconductor layer 26 and the p-type GaInAs layer 3 of the lower multilayer semiconductor layer 5 are removed from the opening through the active layer. Selective etching was performed by using an etching solution of hydrogen peroxide and water so as to reach the upper and lower positions of No. 11. By this selective etching, a DBR (distributed Bragg reflector) composed of a high reflectivity InP layer 4 / air layer 3a (InP layer 25 / air layer 24a) was formed above and below the active layer 11. In the lower multilayer semiconductor layer 5, the InP layer 4 / GaInAs layer 3 remains partially, and in the upper multilayer semiconductor layer 26, the InP layer 25 / GaInAs layer 24
Remains.

Further, as shown by reference numeral 29 in FIG. 5B, an AlGaInAs layer as a buried layer, specifically, a non-doped AlInAs
Layer 19 was selectively oxidized. The AlGaInAs oxide layer 29 further increases the resistance of the buried layer around the active layer 11,
The current can be more efficiently injected into the active layer 11.

Finally, as shown in FIG. 5 (c), the protective film 28 on the active layer 11 is removed to form a light exit window 28a, and a region of the upper multilayer semiconductor layer 26 which is not subjected to the selective etching is removed. The upper protective film 28 was removed to form an AuGeNi n-type electrode 30. Also, the back surface of the p-type InP substrate 1 was polished to form a p-type electrode 31 of AuZnNi.

The characteristics of the surface emitting laser chip thus manufactured were examined. FIG. 6 shows the current vs. light output characteristics and the current vs. voltage characteristics of the surface emitting laser. This surface emitting laser emits light at a wavelength of 1.55 μm,
It was confirmed that the threshold current was lower than that of the surface emitting laser having GaInAsP in the active layer, and that the optical output increased for the same current value. Furthermore, single transverse mode oscillation was confirmed up to the maximum light output. It was also confirmed that similar characteristics could be obtained even when the composition of AlGaInAs and AlGaInP used was changed and the lattice constant was changed in the range of + 10% to 10% with respect to InP.

Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a cross-sectional view showing the structure of the surface emitting laser according to the second embodiment, and FIGS.

The surface emitting laser shown in FIG. 7 has an active layer 42 and a lower multilayer semiconductor layer 36 and an upper multilayer semiconductor layer 57 above and below a structure in which the active layer 42 is buried in a semiconductor.
A p-type electrode layer 61 is provided on the upper multilayer semiconductor layer 57,
An n-type electrode 62 is provided on the back surface of the substrate. Symbol 59 is SiO ₂
A protective film such as film or SiN _X film, reference numeral 59a denotes an exit window of the light.

The lower multilayer semiconductor layer 36 is the first semiconductor layer 3
4 and the second semiconductor layer 35 are alternately stacked, and have a conductive multilayer structure. The first semiconductor layer 34 and the second semiconductor layer 35 partially extend directly under the active layer 42. The first semiconductor layer 34 in the region including
The distributed Bragg reflector (DBR) structure in which a and the second semiconductor layer 35 are alternately stacked. Usually, the first semiconductor layer 34 is an AlGaInAs layer, and the second semiconductor layer 35 is an AGaInAs layer.
This is an lGaInP layer, and the above DBR structure is formed by selectively oxidizing only the AlGaInAs layer 34 up to the optical waveguide portion.

The upper multilayer semiconductor layer 57 is the first semiconductor layer 5
5 and the second semiconductor layer 56 are alternately stacked, and have a conductive multilayer structure. The first semiconductor layer 55 and the second semiconductor layer 56 are left directly above the active layer 42 so that the first semiconductor layer 55 and the second semiconductor layer 56 are partially left. The first semiconductor layer 55 in the region including is oxidized to form a DBR structure in which oxide layers and second semiconductor layers 56 are alternately stacked. Normally, the first semiconductor layer 55 is an AlGaInAs layer, and the second semiconductor layer 56 is an AlGaInP layer. The above DBR is obtained by selectively oxidizing only the AlGaInAs layer 55 up to the optical waveguide portion.
It is formed into a structure.

The structure in which the semiconductor is buried around the active layer 42 has a refractive index waveguide structure in which the average refractive index of the buried portion is higher than the average refractive index of the buried layer. Specifically, the average refractive index of the active layer 42 and the upper and lower multilayer films 40 and 46 is set higher than the average refractive index of the buried layer 48a.
The active layer 42 has an optical waveguide structure.

The buried layer 48a is basically made of p-type AlGaInAsP
And a repetition layer of n-type AlGaInAsP, a semi-insulating AlGaInAsP layer doped with Fe or Cr doping, and an AlGaInAsP oxide layer 60 having an Al composition higher than other layers between these layers.

Further, the buried portion including the active layer 42 having a structure in which the semiconductor is buried around the active layer 42 is made of AlGaIn.
It is composed of As, and has multilayered films 40 and 46 above and below a distributed Bragg reflector structure having a low reflectance.

The surface emitting laser shown in FIG. 7 has the following functions and effects. (1) The distributed Bragg reflector (DBR) is an oxide layer 34a
/ The second semiconductor layer 35 (or the oxide layer 55a / the second semiconductor layer 56), it is possible to increase the difference in the refractive index of the films constituting the DBR and obtain a high reflectance with a small number of pairs. it can. (2) Since a vapor phase epitaxy method or the like having excellent controllability can be applied to the formation of the DBR, highly accurate wavelength control is possible. (3) Since the number of pairs of films constituting the DBR may be small,
The thickness of the surface emitting laser is smaller than that of a semiconductor / semiconductor having a DBR. (4) Since the semiconductor / semiconductor remains in a part of the DBR, an electrode can be provided there and the current can be injected through the DBR. Therefore, it is easy to manufacture a surface emitting laser. (5) Since the active layer 42 has an optical waveguide structure while having a buried structure, a single transverse mode operation is possible. (6) Since the semiconductor / semiconductor remains in part of the lower DBR,
Good heat release. (7) Since the crystal can be grown on the InP substrate 32 with a lattice-matched crystal growth film, a surface-emitting laser with high oscillation characteristics in a long wavelength band and high reliability can be obtained. (8) Since the multilayer films 40 and 46 having a distributed Bragg reflector structure with low reflectivity are provided above and below the active layer 42, current can be uniformly injected and optical waveguide characteristics can be further improved. Efficiency is good because it improves (9) From the above, a high-performance surface-emitting laser in a single transverse mode with a low threshold current and high light output is realized. (10) The buried layer 48a is basically made of p-type AlGaInAsP and n-type Al
Since it is a GaInAsP repeating layer and a semi-insulating AlGaInAsP layer doped with Fe or Cr, the resistance of the buried layer around the active layer 42 is high, and current is efficiently injected into the active layer 42. Furthermore, an AlGaInAs oxide layer 6 having a high Al composition
Since it has 0, the buried layer portion around the active layer 42 has a higher resistance, and current is more efficiently injected into the active layer 42.

Next, an example of a method for manufacturing a surface emitting laser will be described.
The description will be given with reference to FIGS. 8 to 10 on the assumption that the oscillation wavelength is λ = 1.3 μm.

As shown in FIG. 8A, the n-type InP substrate 3
On the n-type InP buffer layer 33, for an oscillation wavelength of λ = 1.3 μm, n of an optical length λ / 4
Al _0.460 Ga _0.008 In _{0.53 2} As layer 34 (first semiconductor layer)
And n-type InP layer with optical length (3/4) λ (second semiconductor layer)
By repeating 3.5 pairs with 35 as a pair, the optical length λ / 4 of only the conductive lower multilayer semiconductor layer 36 (here, the AlGaInAs layer 34 is calculated based on the refractive index of the AlGaInAs oxide, and the n-type In
The P layer 35 is AlGaInP in which the Al composition and the Ga composition are zero. ), N-type InP layer 37 having an optical length of 2λ, n-type Al _x Ga _y In _1-xy As layer 38 and n-type Al _m G a _n In
A 2.5-pair repetitive multilayer film 40 having a pair of _1-mn As layers 39 (in this case, x> m, x + y = m + n, and both layers 38 and 39 are lattice-matched to InP. X> m since it is, towards the layer 38 is an Al composition greater than the layer 39. here, x = 0.468, y = 0 , m = 0.25, .n type is set to _{n = 0.218 Al x Ga y in} 1-xy as layer 38 and n-type Al _m Ga
_{The n} In _1-mn As layer 39 is AlGaInAsP having a P composition of zero. ), Followed by a non-doped Al _x Ga _y In _1-xy As graded layer 4
1 (here, x = 0.2 to 0.4, y = 0.218 to 0.068), Al _0.154 Ga _0.314 In _0.532 As well layer and Al
_0.25 Ga _0.218 In _0.532 active layer of the optical length λ comprised As barrier layer (3QWs) 42 and the spacer layer 43 including, and p-type _{Al x Ga y In 1-xy} As layer 44 and the p-type Al _m Ga _n In
_{The 1-mn} As layer 45 is paired to form a multilayer film 46 in which 2.5 pairs are repeated (in this case, x> m, x + y = m + n,
Both layers 44 and 45 are lattice matched to InP. x> m
Therefore, the layer 44 has a higher Al composition than the layer 45.
Here, x = 0.468, y = 0, m = 0.25, n = 0.218
And p-type _{Al x Ga y In 1-xy} As layer 44 and the p-type Al _m
The Ga _n In _1-mn As layer 45 is made of AlGaInAsP with zero P composition.
It is. ). On top of this, a 600 nm thick SiO ₂ layer 47 is
It was patterned into a circle or a square with a diameter of ２０20 μm.

Next, as shown in FIG. 8 (b), SiO ₂ layer 4
Using the mask 7 as a mask, etching is performed up to the n-type InP layer 37, and as shown in FIG.
P layer 48, 390 nm thick Fe or Cr doped InP layer 4
9. Non-doped AlInAs layer 50 with a thickness of 220 nm, Fe with a thickness of 390 nm
Alternatively, a Cr-doped InP layer 51, a 50-nm thick non-doped InP
By repeating the structure of the P layer 52 twice, buried growth was made around the active layer 42. Here, reference numeral 53 represents the second structure of the layers 48 to 52.

The layers 48 to 52 are basically made of AlGaInAsP and Fe or Cr-doped semi-insulating AlGaInAsP, while the layers 48 and 52 have zero Al, Ga and As compositions.
AlGaInAsP, and layers 49 and 52 are Fe or Cr doped semi-insulating AlG with zero Al, Ga and As compositions.
The non-doped AlInAs layer 50 is AlGaInAsP having a Ga composition and a P composition of zero. The non-doped AlInAs layer 50 has a higher Al composition than the other layers 48 to 49 and 51 to 52.

Next, as shown in FIG._TwoLayer 4
7, the p-type InP layer 5 having an optical wavelength of 2λ is removed.
4. Subsequent to this, p-type Al having an optical length of λ / 4_0.460Ga
_0.008In _0.532As layer 55 (first semiconductor layer) and optical length
(3/4) λ p-type InP layer (second semiconductor layer) 56
2.5 pairs repeated as a
The body layer 57 was grown. Here, only the AlGaInAs layer 55 is optical.
The length λ / 4 is calculated based on the refractive index of AlGaInAs oxide,
The InP layer 56 is made of AlGaInP in which the Al composition and the Ga composition are zero.
You.

Next, as shown in FIG. 9 (b), SiO ₂ layer 5
By using 8 as a mask, a mesa of 50 μmφ was formed by etching by the thickness of the surface emitting laser. At the time of this etching, a mesa was formed such that an active layer portion was included inside the mesa and the active layer portion was deviated from the center of the mesa. After that, as shown in FIG.
SiN _X or SiO ₂ was deposited on the entire surface as a protective film 59.

After the entire surface of the protective film 59 is deposited, as shown in FIG. 10A, an opening is formed by selectively etching the protective film 59 on the mesa end closer to the active layer (left side in the figure). did.

After the opening is formed, only the p-type AlGaInAs layer 55 of the upper multilayer semiconductor layer 57 and the n-type AlGaInAs layer 34 of the lower multilayer semiconductor layer 36 are selectively oxidized as shown in FIG. AlGaInAs from the part to the top and bottom of the active layer 42
The oxide layers 34a and 55a were formed. Further, as shown by reference numeral 60, the AlGaInAs layer of the buried layer, specifically, the non-doped AlInAs layer 50 was selectively oxidized.

By this selective oxidation, the high reflectance InP layer 3
A DBR (distributed Bragg reflector) composed of 5 / AlGaInAs oxide layer 34a (InP layer 56 / AlGaInAs oxide layer 55a) was partially formed above and below active layer 42. In the lower multilayer semiconductor layer 36, an InP layer 35 / AlGaInAs layer 34 is partially formed.
And the upper multi-layer semiconductor layer 57 partially includes the InP layer 56 /
The AlGaInAs layer 55 remains.

Further, in the buried layer, since the Al composition of the AlInAs layer 50 is high, a high-resistance oxide layer 60 is formed on the entire surface around the active layer 42, and the buried layer portion has a higher resistance, and The current can be more efficiently injected into the layer 42.

Finally, as shown in FIG. 10 (c), the protective film 59 on the active layer 42 is removed to form a light exit window 59a. The upper protective film 59 is removed, and the AuZnNi p-type electrode 6 is removed.
1 was formed. The back surface of the n-type InP substrate 32 was polished to form an AuGeNi n-type electrode 62.

The characteristics of the surface emitting laser chip thus manufactured were examined. This surface-emitting laser emits light at a wavelength of 1.3 μm, and, similarly to the first embodiment, a conventional GaInAsP
Threshold current is lower than that of a surface emitting laser having
It was also confirmed that the light output increased for the same current value. Furthermore, single transverse mode oscillation was confirmed up to the maximum light output. It was also confirmed that similar characteristics could be obtained even when the composition of AlGaInAs and AlGaInP used was changed and the lattice constant was changed in the range of + 10% to 10% with respect to InP.

[Third Embodiment] A third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a cross-sectional view showing the structure of the surface emitting laser according to the third embodiment, and FIGS.

The surface emitting laser shown in FIG.
A lower multilayer semiconductor layer 67 and an upper multilayer semiconductor layer 88 are provided above and below a structure in which a semiconductor layer and an active layer 73 are embedded. A p-type electrode layer 92 is provided on the upper multilayer semiconductor layer 57, and an n-type electrode 93 is provided on the back surface of the substrate. Symbol 90 is
A protection film such as a SiO ₂ film or a SiN _X film is shown, and reference numeral 90a indicates a light emission window.

The lower multilayer semiconductor layer 67 is the first semiconductor layer 6
5 and the second semiconductor layer 66 are alternately stacked, and have a conductive multilayer structure, and the first semiconductor layer 65 / the second semiconductor layer 66 are left directly below the active layer 73 so as to leave the first semiconductor layer 65 / the second semiconductor layer 66 partially. Is oxidized in the first semiconductor layer 65 in the region including
And a second semiconductor layer 66 are alternately stacked to form a distributed Bragg reflector (DBR) structure. Usually, the first semiconductor layer 65 is an AlGaInAs layer and the second semiconductor layer 66 is an AlGaInAs layer.
This is an aInP layer, and the above DBR structure is formed by selectively oxidizing only the AlGaInAs layer 65 up to the optical waveguide portion.

The upper multilayer semiconductor layer 88 is the first semiconductor layer 8
6 and a second semiconductor layer 87 are alternately stacked, and have a conductive multi-layer structure. The first semiconductor layer 86 and the second semiconductor layer 87 are left directly above the active layer 73 so as to leave a part thereof. Is oxidized in the region including the first semiconductor layer 86 to form the oxide layer 86a
And a second semiconductor layer 87 are alternately stacked to form a DBR structure. Usually, the first semiconductor layer 86 is made of AlGaInAs
The second semiconductor layer 87 is an AlGaInP layer,
Only the layer 86 is selectively oxidized to the optical waveguide portion to form the above-mentioned DBR structure.

The structure in which the semiconductor is buried around the active layer 73 has a refractive index waveguide structure in which the average refractive index of the buried portion is higher than the average refractive index of the buried layer. Specifically, the average refractive index of the active layer 73 and the upper and lower multilayer films 71 and 77 is made higher than the average refractive index of the buried layer 79a.
It has an optical waveguide structure.

The buried layer 79a is basically made of p-type AlGaInAsP
And a repetitive layer of n-type AlGaInAsP, a semi-insulating AlGaInAsP layer doped with Fe or Cr doping, and an AlGaInAsP oxide layer 91 having an Al composition higher than other layers between these layers.

Further, the buried portion including the active layer 73 having the structure in which the semiconductor is buried around the active layer 73 is made of AlGaIn.
It is composed of As, and has multilayered films 71 and 77 of a distributed Bragg reflector structure with low reflectivity above and below it.

The surface emitting laser shown in FIG. 11 has the following functions and effects. (1) The distributed Bragg reflector (DBR) is an oxide layer 65a
/ The second semiconductor layer 66 (or the oxide layer 86a / the second semiconductor layer 87), it is possible to increase the refractive index difference between the films constituting the DBR and obtain a high reflectance with a small number of pairs. it can. (2) Since a vapor phase epitaxy method or the like having excellent controllability can be applied to the formation of the DBR, highly accurate wavelength control is possible. (3) Since the number of pairs of films constituting the DBR may be small,
The thickness of the surface emitting laser is smaller than that of a semiconductor / semiconductor having a DBR. (4) Since the semiconductor / semiconductor remains in a part of the DBR, an electrode can be provided there and the current can be injected through the DBR. Therefore, it is easy to manufacture a surface emitting laser. (5) Since the active layer 73 has the buried structure and is the optical waveguide type structure, a single transverse mode operation is possible. (6) Since the semiconductor / semiconductor remains in part of the lower DBR,
Good heat release. (7) Since the crystal can be grown on the GaAs substrate 63 with a lattice-matched crystal growth film, a surface emitting laser having a characteristic capable of oscillating in a short wavelength pair and a high reliability can be obtained. (8) Since the multilayer films 71 and 77 having a low reflectivity distributed Bragg reflector structure are provided above and below the active layer 73, uniform current injection is possible, and the optical waveguide characteristics are further improved. Efficiency is good because it gets better. (9) From the above, a high-performance surface-emitting laser in a single transverse mode with a low threshold current and high light output is realized. (10) The buried layer 79a is basically made of p-type AlGaInAsP and n-type Al
Because of the GaInAsP repeating layer and the semi-insulating AlGaInAsP layer doped with Fe or Cr doping, the resistance of the buried layer around the active layer 73 is high, and current is efficiently injected into the active layer 73. Furthermore, an AlGaInAs oxide layer 9 having a high Al composition
As a result, the buried layer around the active layer 73 has a higher resistance, and current is more efficiently injected into the active layer 73.

Next, an example of a method for manufacturing a surface emitting laser will be described.
An explanation will be given with reference to FIGS. 12 to 14 assuming that the oscillation wavelength is λ = 0.85 μm.

As shown in FIG. 12A, an n-type GaAs buffer layer 64 is provided on an n-type GaAs substrate 63. For an oscillation wavelength of λ = 0.85 μm, n of an optical length λ / 4
Type Al _0.9 Ga _0.1 As layer 65 (first semiconductor layer) and optical length (3
/ 4) λ n-type Ga _0.5 In _0.5 P layer (second semiconductor layer) 66
Is repeated as a pair, and the conductive lower multilayer semiconductor layer 67 (here, only the optical length λ / 4 of the AlGaAs layer 65 is calculated based on the refractive index of the AlGaAs oxide, and the n-type AlGaAs layer 6
Numeral 5 is AlGaInAs having an In composition of zero, and the n-type GaInP layer 66 is AlGaInP having an Al composition of zero. ), N-type Ga _0.5 In _0.5 P layer 68 having an optical length of 2λ, n-type Al _0.5 Ga _0.5 As layer 69 and n-type Al _0.15 Ga _0.85 As layer 70
(A layer 69 has a larger Al composition than the layer 70. In this case, n-type Al
_{The 0.5} Ga _0.5 As layer 69 and the n-type Al _0.5 Ga _0.5 As layer 70 have the In composition.
AlGaInAsP with zero P composition. Subsequently, a non-doped Al _x Ga _{1 -x} As inclined layer 72 (here, x = 0.3 to 0.4), a GaAs well layer and
A spacer layer 74 including an active layer (3QWs) 73 having an optical length of λ composed of an Al _0.3 Ga _0.7 As barrier layer, and a p-type Al _0.5 Ga _0.5 As layer 75 and a p-type Al _0.15 Ga _0.85 As layer 76
Are formed as a pair, and a multilayer film 77 in which 2.5 pairs are repeated (in this case, the layer 75 has a higher Al composition than the layer 76. p-type Al
_{The 0.5} Ga _0.5 As layer 75 and the p-type Al _0.15 Ga _0.85 As layer 76 are AlGaInAsP with zero In composition and no P composition. ). On top of this, a 600 nm thick SiO ₂ layer 78 is
It was patterned into a circle or a square with a diameter of ２０20 μm.

Next, as shown in FIG. 12B, etching is performed up to the n-type Ga _0.5 In _0.5 P layer 68 using the SiO ₂ layer 78 as a mask, and as shown in FIG. 50 nm thick non-doped Ga _0.5 In _0.5 P layer 79, 220 nm thick Fe or
Cr-doped Ga _0.5 In _0.5 P layer 80, non-doped 120 nm thick
Al _0.98 Ga _0.02 As layer 81, 220 nm thick Fe or Cr doped Ga _0.5 In _0.5 P layer 82, 50 nm thick non-doped Ga _0.5 In
The structure of the _0.5 P layer 83 was repeated twice to bury and grow around the active layer 73. Here, reference numeral 84 denotes 2 of layers 79 to 83
Represents the structure of the round.

The layers 79 to 83 are basically made of AlGaInAsP, but the layers 79, 80, 82 and 83 are made of AlGaInAsP.
The Al composition and the As composition were made zero, and the layer 81 was made of AlG
The In composition and the P composition of aInAsP were made zero.

The layers 79 to 83 are basically made of AlGaInAsP and semi-insulating AlGaInAsP doped with Fe or Cr, while the layers 79 and 83 are made of AlGaInAsP having an Al composition and an As composition of zero.
P, the layers 80 and 83 are Fe or Cr doped semi-insulating AlGaInAsP with zero Ga composition and As composition, and the non-doped AlGaAs layer 81 is Al with zero In composition and P composition.
GaInAsP. The non-doped AlGaAs layer 81 is the other layer 79
Al composition is higher than -80 and 82-63.

Next, as shown in FIG. 13A, after removing the mask of the SiO ₂ layer 78, the p-type Ga _0.5 I having an optical wavelength of 2λ is used.
An n _0.5 P layer 85 is grown, followed by an optical length λ / 4.
P-type Al _0.9 Ga _0.1 As layer 86 (first semiconductor layer) and the optical length (3/4) p-type Ga _0.5 In _{0 .5} P layer of lambda (second semiconductor layer)
The conductive upper multilayer semiconductor layer 88 was grown by repeating 2.5 pairs with 87 as a pair. Here, the optical length λ / 4 of the AlGaAs layer 86 is calculated based on the refractive index of the AlGaAs oxide,
The type Al _0.9 Ga _0.1 As layer 86 is AlGaInAs with the In composition being zero, and the p-type Ga _0.5 In _0.5 P layer 87 is A with the Al composition being zero.
lGaInP.

Next, as shown in FIG. 13B, a mesa of 50 μmφ was formed by etching using the SiO ₂ layer 89 as a mask by the thickness of the surface emitting laser. At the time of this etching, a mesa was formed such that an active layer portion was included inside the mesa and the active layer portion was deviated from the center of the mesa. Thereafter, as shown in FIG. 13C, SiN _X or SiO ₂ was entirely deposited as a protective film 90 by a plasma CVD method.

After the entire surface of the protective film 90 is deposited, as shown in FIG. 14A, an opening is formed by selectively etching the protective film 90 on the mesa end closer to the active layer portion (left side in the figure). did.

After the opening is formed, the p-type AlGaAs layer 86 of the upper multilayer semiconductor layer 88 and the n-type AlGaAs layer 65 of the lower multilayer semiconductor layer 67 are selectively oxidized as shown in FIG.
AlGaAs oxide layer 6 extending from the opening to above and below active layer 73
5a and 86a were formed. As shown by reference numeral 91, an AlGaInAs layer of a buried layer, specifically, a non-doped AlGaAs
Layer 81 was selectively oxidized.

By this selective oxidation, Ga _0.5 In of high reflectivity is obtained.
_0.5 P layer 66 / AlGaAs oxide layer 65a (Ga _0.5 In _0.5 P layer 8
7 / AlGaAs oxide layer 86a) and DBRs (distributed Bragg reflectors) were partially formed above and below active layer 73. In the lower multi-layer semiconductor layer 67, Ga _0.5 In _0.5 P layer 6 is partially formed.
6 / AlGaAs layer 65 remains, and Ga _0.5 In _0.5 P layer 87 / AlGaAs layer 86 partially remains in upper multilayer semiconductor layer 88.

In the buried layer, non-doped Al _0.98 Ga _0.02
Since the Al composition of the As layer 81 is high, a high-resistance oxide layer 91 is formed on the entire surface around the active layer 73, and the buried layer portion has a higher resistance, so that the current is more efficiently injected into the active layer 73. It became possible to do.

Finally, as shown in FIG. 14C, the protective film 90 on the active layer 73 is removed to form a light exit window 90a, and a region of the upper multilayer semiconductor layer 88 which has not been selectively oxidized is exposed. The upper protective film 90 is removed, and the AuZnNi p-type electrode 9 is removed.
2 was formed. Also, the back surface of the n-type GaAs substrate 63 was polished to form an AuGeNi n-type electrode 93.

The characteristics of the surface emitting laser chip thus manufactured were examined. This surface-emitting laser emits light at a wavelength of 0.85 μm, has a threshold current lower by about 10% and an optical output about 20% higher than that of a conventional oxidation type AlGaAs-based surface-emitting laser having good characteristics. % Was confirmed to be low. Furthermore, single transverse mode oscillation was confirmed up to the maximum light output.

[0075]

As described above, according to the surface emitting laser of the present invention and the method of manufacturing the same, the following effects can be obtained. (1) The structure of the distributed Bragg reflector (DBR) is semiconductor /
Since it is an air layer or a semiconductor / oxide layer, a high reflectance can be obtained with a small number of pairs by increasing the difference in refractive index between the films constituting the DBR. (2) Since a vapor phase epitaxy method or the like having excellent controllability can be applied to the formation of the DBR, highly accurate wavelength control is possible. (3) Since the number of pairs of films constituting the DBR may be small,
The thickness of the surface emitting laser is smaller than that of a semiconductor / semiconductor having a DBR. (4) Since the semiconductor / semiconductor remains in a part of the DBR, an electrode can be provided there and the current can be injected through the DBR. Therefore, it is easy to manufacture a surface emitting laser. (5) Single lateral mode operation is possible because the active layer is an optical waveguide type structure with a buried structure. (6) Since the semiconductor / semiconductor remains in part of the lower DBR,
Good heat release. (7) Since the semiconductor / semiconductor remains in part of the DBR, the thickness of the semiconductor / oxide layer does not change due to steam oxidation. (8) Since it can be grown on an InP substrate with a lattice-matched crystal growth film, a surface emitting laser with high oscillation characteristics in a long wavelength band and high reliability can be obtained. (9) In addition, since a multilayer film having a distributed Bragg reflector structure with a low reflectance is provided above and below the active layer, uniform current injection is possible, and the optical waveguide characteristics are further improved, so that the efficiency is high. . (10) From the above, a high-performance surface-emitting laser in a single transverse mode with a high light output at a low threshold current is realized. (11) When the buried layer is a repetitive layer of p-type AlGaInAsP and n-type AlGaInAsP, or a semi-insulating AlGaInAsP layer doped with Fe or Cr, the resistance of the buried layer around the active layer is high, Current is efficiently injected into the layer.
Further, when an AlGaInAs oxide layer having a high Al composition is provided between these layers, the buried layer around the active layer has a higher resistance, and current is more efficiently injected into the active layer.

[Brief description of the drawings]

FIG. 1 is a sectional view of a surface emitting laser according to a first embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a process chart of a method for manufacturing a surface emitting laser according to the first embodiment of the present invention.

FIG. 4 is a process chart of a method for manufacturing a surface emitting laser according to the first embodiment of the present invention.

FIG. 5 is a process chart of a method for manufacturing a surface emitting laser according to the first embodiment of the present invention.

FIG. 6 is a view showing current-voltage characteristics and current-optical output characteristics of the surface emitting laser according to the first embodiment of the present invention.

FIG. 7 is a sectional view of a surface emitting laser according to a second embodiment of the present invention.

FIG. 8 is a process chart of a method for manufacturing a surface emitting laser according to a second embodiment of the present invention.

FIG. 9 is a process chart of a method for manufacturing a surface emitting laser according to a second embodiment of the present invention.

FIG. 10 is a process chart of a method for manufacturing a surface emitting laser according to a second embodiment of the present invention.

FIG. 11 is a sectional view of a surface emitting laser according to a third embodiment of the present invention.

FIG. 12 is a process chart of a method for manufacturing a surface emitting laser according to a third embodiment of the present invention.

FIG. 13 is a process chart of a method for manufacturing a surface emitting laser according to a third embodiment of the present invention.

FIG. 14 is a process chart of a method for manufacturing a surface emitting laser according to a third embodiment of the present invention.

[Explanation of symbols]

_{Reference Signs List} 1 p-type InP substrate 2 p-type InP buffer layer 3 first semiconductor layer (p-type Ga _0.468 In _{0.532 with} optical length λ / 4 ₎
As layer) 3a air layer 4 a second semiconductor layer (optical length (3/4) of the p-type InP layer) 5 p-type InP layer 7 p-type lower multilayer semiconductor layer 6 optical length 2λ of λ Al _x Ga _y In _1-xy As layer 8 p-type Al _m Ga _n In _1-mn As layer 9 multilayer film 10 non-doped Al _x Ga _y In _1-xy As inclined layer 11 active layer (3QWs) having optical length λ 12 spacer layer 13 n type _{Al x Ga y In 1-xy} As layer 14 n-type _{Al m Ga n In 1-mn} As layer 15 multilayer film 16 SiO ₂ layer 17 p-type InP layer 17a buried layer 18 n-type InP layer 19 doped AlInAs layer 20 n-type InP layer 21 p-type InP layer 22 second buried growth structure 23 n-type InP layer with optical length 2λ 24 first semiconductor layer (n-type Ga _0.468 In with optical length λ / 4)
_0.532 As layer) 24a Air layer 25 Second semiconductor layer (n-type InP layer with optical length (3/4) λ) 26 Upper multilayer semiconductor layer 27 SiO ₂ layer 28 Protective layer (SiO ₂ or SiN _x ) 28a Light emission Window 29 oxide layer of buried layer 30 n-type electrode 31 p-type electrode 32 n-type InP substrate 33 n-type InP buffer layer 34 first semiconductor layer (n-type Al _0.460 Ga having an optical length of λ / 4)
_0.008 In _0.532 As layer) 34a Oxide 35 Second semiconductor layer (n-type InP layer with optical length (3/4) λ) 36 Lower multilayer semiconductor layer 37 n-type InP layer with optical length 2λ 38 n-type Al _x Ga _y In _1-xy As layer 39 n-type Al _m Ga _n In _1-mn As layer 40 multilayer film 41 non-doped Al _x Ga _y In _1-xy As inclined layer 42 active layer (3QWs) with optical length λ 43 spacer layer 44 p-type Al _x Ga _y In _1-xy As layer 45 p-type Al _m Ga _n In _1-mn As layer 46 multilayer film 47 SiO ₂ layer 48 non-doped InP layer 48a buried layer 49 Fe or Cr non-doped InP layer 50 non-doped AlInAs Layer 51 Fe or Cr non-doped InP layer 52 Non-doped InP layer 53 Second buried growth structure 54 n-type InP layer having an optical length of 2λ 55 First semiconductor layer (p-type Al _0.460 Ga having an optical length of λ / 4)
_0.008 In _0.532 As layer) 55a Oxide layer 56 Second semiconductor layer (p-type InP layer having an optical length of (3/4) λ) 57 Upper multilayer semiconductor layer 58 SiO ₂ layer 59 Protective layer (SiO ₂ or SiN _x ) 59a Light emission window 60 Oxide layer of buried layer 61 P-type electrode 62 N-type electrode 63 n-type GaAs substrate 64 n-type GaAs buffer layer 65 First semiconductor layer (n-type Al _0.9 Ga _{0.1 having} optical length λ / 4) As
Layer 65a oxide 66 second semiconductor layer (n-type Ga _0.5 In having an optical length of (3/4) λ)
_0.5 P layer) 67 Lower multilayer semiconductor layer 68 n-type Ga _0.5 In _0.5 P layer having an optical length of 2λ 69 n-type Al _0.5 Ga _0.5 As layer 70 n-type Al _0.15 Ga _0.85 As layer 71 multilayer film 72 non-doped Al _x Ga _{1− x} As gradient layer 73 Active layer with optical length λ (3QWs) 74 Spacer layer 75 p-type Al _0.5 Ga _0.5 As layer 76 p-type Al _0.15 Ga _0.85 As layer 77 multilayer film 78 SiO ₂ layer 79 undoped Ga _0.5 In _0.5 P layer 79a buried layer 80 Fe or Cr non-doped Ga _0.5 In _0.5 P layer 81 non-doped Al _0.98 Ga _0.02 As layer 82 Fe or Cr non-doped Ga _0.5 In _0.5 P layer 83 non-doped Ga _0.5 In _0.5 P layer 84 Second buried growth structure 85 n-type Ga _0.5 In _0.5 P layer having an optical length of 2λ 86 first semiconductor layer (p-type Al _0.9 Ga _0.1 As having an optical length of λ / 4
Layer) 86a oxide layer 87 second semiconductor layer (p-type Ga _0.5 In of optical length (3/4) λ)
_0.5 P layer) 88 Upper multilayer semiconductor layer 89 SiO ₂ layer 90 Protective layer (SiO ₂ or SiN _x ) 90 a Light emission window 91 Oxide layer of buried layer 92 p-type electrode 93 n-type electrode

Continued on the front page (72) Inventor Hiroyuki Uenohara 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Toshiaki Kagawa 3-192-1, Nishishinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation F-term (reference) 5F073 AA12 AA65 AA74 AB02 AB17 CA14 CA15 CB02 EA29

Claims (8)

[Claims] A conductive upper multilayer semiconductor layer in which a first semiconductor layer and a second semiconductor layer are alternately stacked above and below an active layer and a structure in which the active layer is embedded in a semiconductor; One semiconductor layer and a second semiconductor layer having a conductive lower multilayer semiconductor layer alternately laminated, having an electrode layer on the upper multilayer semiconductor layer, the upper multilayer semiconductor layer is The first semiconductor layer in a region including immediately above the active layer is removed, and a distributed Bragg reflector structure in which an air layer and a second semiconductor layer are alternately stacked, and the lower multilayer semiconductor The layer is characterized in that the first semiconductor layer in a region including immediately below the active layer is removed, and a distributed Bragg reflector structure in which an air layer and a second semiconductor layer are alternately stacked. Surface emitting laser. 2. A conductive upper multilayer semiconductor layer in which a first semiconductor layer and a second semiconductor layer are alternately stacked above and below an active layer and a structure in which the active layer is embedded in a semiconductor. A conductive lower multilayer semiconductor layer in which one semiconductor layer and a second semiconductor layer are alternately stacked; and an electrode layer on the upper multilayer semiconductor layer; The first semiconductor layer in the region including immediately above the layer is oxidized,
An oxide layer and a second semiconductor layer are alternately stacked to form a distributed Bragg reflector structure, and the lower semiconductor layer is a first semiconductor layer in a region including immediately below the active layer. Is oxidized to form a distributed Bragg reflector structure in which oxide layers and second semiconductor layers are alternately stacked. 3. The first semiconductor layer of the upper multilayer semiconductor layer is AlGaInAs, the second semiconductor layer is AlGaInP, and the first semiconductor layer of the lower multilayer semiconductor layer is AlGaInP.
3. The surface emitting laser according to claim 1, wherein the second semiconductor layer is GaInAs, and the second semiconductor layer is AlGaInP. 4. The structure in which a semiconductor is buried around the active layer is a refractive index waveguide structure in which the average refractive index of the buried portion is higher than the average refractive index of the buried layer. The surface emitting laser according to claim 1. 5. A buried layer comprising p-type AlGaInAsP and n-type AlGaInAs
Repeated layer of P, Fe or Cr doped semi-insulating
5. The surface emitting laser according to claim 1, further comprising an AlGaInAsP layer, or an AlGaInAs oxide layer having a higher Al composition than other buried layers between these layers. . 6. A buried portion including an active layer having a structure in which a semiconductor is buried around the active layer is made of AlGaInAs, and has a distributed Bragg reflecting mirror structure with low reflectance above and below it. The surface emitting laser according to claim 1, 2, or 3. 7. The method of manufacturing a surface emitting laser according to claim 1, wherein the upper and lower distributed Bragg reflector structures are formed by alternately stacking AlGaInAs layers and AlGaInP layers. A method of manufacturing a surface emitting laser, wherein only the AlGaInAs layers of the upper and lower multilayer semiconductor layers are selectively etched to the optical waveguide portion. 8. The method for manufacturing a surface emitting laser according to claim 2, wherein the upper and lower distributed Bragg reflector structures are formed by alternately stacking AlGaInAs layers and AlGaInP layers. A method for manufacturing a surface-emitting laser, wherein an Al composition is increased only in an AlGaInAs layer of a semiconductor layer and selective oxidation is performed up to an optical waveguide portion.