CN103972340B - Nitride semiconductor structure and semiconductor light emitting element - Google Patents

Abstract

The present invention relates to a nitride semiconductor structure and a semiconductor light-emitting element. The nitride semiconductor structure comprises an N-type semiconductor layer and a P-type semiconductor layer, a light-emitting layer is arranged between the N-type semiconductor layer and the P-type semiconductor layer, a hole-providing layer is arranged between the light-emitting layer and the P-type semiconductor layer, the hole-providing layer is indium gallium nitride In _x Ga _1‑x N (0<x<1), and the hole-providing layer is doped with a fourth main group element at a concentration of 10 ¹⁷ ‑10 ²⁰ cm ^‑3 . The semiconductor light-emitting element comprises the above-mentioned nitride semiconductor structure on a substrate, and an N-type electrode and a P-type electrode that cooperate to provide electrical energy. By doping with the fourth main group element, the hole concentration can be increased, and the inactivation phenomenon caused by Mg‑H bonding can be reduced, so that Mg is activated and has an effective acceptor function, thereby increasing the luminous efficiency.

Description

Nitride semiconductor structure and semiconductor light emitting element

technical field

The invention relates to a nitride semiconductor structure and a semiconductor light-emitting element, in particular to a nitride semiconductor structure with a hole supply layer and a semiconductor light-emitting element, and belongs to the field of semiconductor technology.

Background technique

In recent years, the application of light-emitting diodes has become more and more extensive, and has become an indispensable and important component in daily life; and light-emitting diodes are expected to replace today's lighting equipment and become the solid-state lighting components of the new generation in the future, so the development of high energy-saving, high-efficiency and Higher power light-emitting diodes will be the future trend; nitride LEDs have become one of the most emerging optoelectronic semiconductor materials due to their small size, no mercury pollution, high luminous efficiency, and long life. The emission wavelength of the compound almost covers the range of visible light, making it a very potential light-emitting diode material.

Materials such as the third main group nitrides such as indium nitride (InN), gallium nitride (GaN) and aluminum nitride (AlN) have a wide energy band gap and play a very important role in optoelectronic semiconductor devices. The range ranges from InN with a direct bandgap of 0.7eV, to GaN at 3.4eV, and even AlN at 6.2eV. The wavelengths of light emitted range from red, green, blue, to deep ultraviolet; and the third main group nitride semiconductor is used as A PN junction is required on the light-emitting element. Specifically, an N-type nitride semiconductor layer and a P-type nitride semiconductor layer must be formed, and the N-type nitride semiconductor layer is generally formed by doping an N-type dopant such as Si or Sn. , and in forming the P-type nitride semiconductor layer, Mg is generally used as the P-type dopant; however, Mg is easy to bond with H to form magnesium-hydrogen complexes (Mg-H Complexes), resulting in the above-mentioned P-type dopant The substance cannot play the nature of the acceptor, resulting in a sharp drop in the hole concentration provided, making the light-emitting element unable to perform normally, and therefore the P-type nitride semiconductor layer with low resistance (low-resistance) is not easy to pass through the traditional technology to form.

For example, when forming a semiconductor layer composed of P-type nitride (such as gallium nitride), NH ₃ gas is usually used as a source of nitrogen. In the epitaxy process (such as vapor deposition, etc.), high temperature It will cause _NH3 to decompose to produce nitrogen atoms and hydrogen atoms, and the hydrogen atoms will form bonds with the P-type dopants (such as Mg) used as acceptors in the above-mentioned semiconductor layer, so that the above-mentioned P-type dopants lose their effect, resulting in The doping concentration cannot be effectively improved; moreover, because the activation energy of magnesium in gallium nitride is very large, the efficiency of hole activation is extremely low (less than 10%); so the hole concentration of P-type gallium nitride is difficult to achieve. Therefore, in order to obtain a high hole concentration, the combination of Mg and H must be reduced, so that P-type GaN can exhibit a sufficiently low impedance, thereby achieving better luminous efficiency.

In view of the fact that the existing nitride semiconductor light-emitting elements still have many deficiencies in practical implementation, developing a new type of nitride semiconductor light-emitting element is still one of the problems to be solved in this field.

Contents of the invention

In order to solve the above-mentioned technical problems, the main purpose of the present invention is to provide a nitride semiconductor structure, which can increase the hole concentration by doping the fourth main group element through the hole-providing layer, and reduce the Mg-H bond caused by The non-activation phenomenon activates Mg to have an effective role as an acceptor, thereby making the hole-providing layer have a higher hole concentration, thereby providing more holes to enter the light-emitting layer, increasing the electron-hole combination, and obtaining a good luminous efficiency.

Another object of the present invention is to provide a semiconductor light-emitting device, which at least includes the above-mentioned nitride semiconductor structure.

To achieve the above object, the present invention provides a nitride semiconductor structure, which includes an N-type semiconductor layer and a P-type semiconductor layer, and a light-emitting layer is arranged between the N-type semiconductor layer and the P-type semiconductor layer, so A hole-providing layer is arranged between the light-emitting layer and the P-type semiconductor layer, and the hole-providing layer is Indium Gallium Nitride In _x Ga _1-x N, where 0<x<1, and the hole-providing layer The layer is doped with group IV elements at a concentration of 10 ¹⁷ -10 ²⁰ cm ^-3 .

According to a specific embodiment of the present invention, preferably, in the above nitride semiconductor structure, the fourth main group element is carbon.

According to a specific embodiment of the present invention, preferably, in the above nitride semiconductor structure, the hole providing layer is doped with a P-type dopant with a concentration greater than 10 ¹⁸ cm ⁻³ .

According to a specific embodiment of the present invention, preferably, in the above nitride semiconductor structure, the P-type dopant is magnesium.

According to a specific embodiment of the present invention, preferably, in the above-mentioned nitride semiconductor structure, the light-emitting layer has a multiple quantum well structure, and the energy gap of the hole providing layer is larger than that of the well layer of the multiple quantum well structure. Energy gap.

According to a specific embodiment of the present invention, preferably, in the above nitride semiconductor structure, the thickness of the hole providing layer is 1-100 nm.

According to a specific embodiment of the present invention, preferably, in the above nitride semiconductor structure, the hole supply layer is Indium Gallium Nitride In _x Ga _1-x N, where x is 0<x≤0.1.

According to a specific embodiment of the present invention, preferably, in the above-mentioned nitride semiconductor structure, a P-type carrier blocking layer is arranged between the hole supply layer and the P-type semiconductor layer, and the P-type carrier blocking layer A layer is made of a material with a higher energy gap than the light-emitting layer.

According to a specific embodiment of the present invention, preferably, in the above-mentioned nitride semiconductor structure, an N-type carrier blocking layer is arranged between the light-emitting layer and the N-type semiconductor layer, and the N-type carrier blocking layer is composed of made of a material having an energy gap higher than that of the light-emitting layer.

According to a specific embodiment of the present invention, preferably, in the above-mentioned nitride semiconductor structure, an N-type carrier blocking layer is arranged between the light-emitting layer and the N-type semiconductor layer, and the N-type carrier blocking layer is composed of made of a material having an energy gap higher than that of the light-emitting layer.

In the present invention, the nitride semiconductor structure includes an N-type semiconductor layer and a P-type semiconductor layer, a light-emitting layer is arranged between the N-type semiconductor layer and the P-type semiconductor layer, and the light-emitting layer and the A hole-providing layer is arranged between the P-type semiconductor layers, and the hole-providing layer is indium gallium nitride In _x Ga _1-x N, where 0<x<1, preferably, the value range of x is 0<x≤ 0.1; In addition, the hole-providing layer is doped with the fourth main group element with a concentration of 10 ¹⁷ -10 ²⁰ cm ^-3 , if the doping concentration of the fourth main group element is less than 10 ¹⁷ cm ^-3 , it cannot have holes For the effect provided, if the doping concentration of the fourth main group element is greater than 10 ²⁰ cm ^-3 , the problem of high resistance value will occur. The preferred doping concentration is 8×10 ¹⁷ -5×10 ¹⁸ cm ^-3 , where , the fourth main group element may be, for example, carbon.

In addition, the above-mentioned hole-providing layer is doped with a P-type dopant with a concentration greater than 10 ¹⁸ cm ⁻³ , and the thickness of the hole-providing layer is 1-100 nm; wherein the P-type dopant can be, for example, magnesium.

In an embodiment of the present invention, the multiple quantum well structure can be formed by alternately stacking the well layer of InGaN and the barrier layer of GaN; and the energy gap of the hole supply layer is larger than that of the multiple quantum well structure. The energy gap of the layer allows holes to enter the well layer of the multiple quantum well structure to increase the combination probability of electrons and holes and further improve the luminous efficiency.

In addition, in an embodiment of the present invention, a P-type carrier blocking layer (for example, P-type aluminum gallium nitride, etc.) may be arranged between the hole supply layer and the P-type semiconductor layer, and the P-type carrier blocking layer consists of It is made of a material with an energy gap greater than that of the light-emitting layer. For example, when the light-emitting layer is a multiple quantum well structure, the energy gap of the P-type carrier blocking layer is greater than the energy gap of the barrier layer of the multiple quantum well structure. To prevent electrons from escaping into the P-type semiconductor layer, it has the effect of slowing down the electron movement rate and increasing the time of staying in the light-emitting layer; and an N-type carrier blocking layer (such as N-type aluminum gallium nitride, etc.), and the N-type carrier blocking layer is made of a material with an energy gap larger than the light-emitting layer. Similarly, the N-type carrier blocking layer is made of a material with an energy gap higher than the light-emitting layer. It is made to prevent holes from escaping into the N-type semiconductor layer, so as to increase the probability of electron-hole combination.

The present invention also provides a semiconductor light emitting element, which at least includes:

a substrate;

an N-type semiconductor layer configured on the substrate;

a light-emitting layer configured on the N-type semiconductor layer;

A hole supply layer, which is arranged on the light-emitting layer, the hole supply layer is indium gallium nitride In _x Ga _1-x N, wherein 0<x<1, and the hole supply layer is doped with Group IV elements at a concentration of 10 ¹⁷ -10 ²⁰ cm ^-3 ;

a P-type semiconductor layer configured on the hole-providing layer;

an N-type electrode disposed on the N-type semiconductor layer in ohmic contact; and

A P-type electrode is configured on the P-type semiconductor layer by ohmic contact.

The semiconductor light-emitting element of the present invention includes the above-mentioned nitride semiconductor structure on a substrate, and two N-type electrodes and P-type electrodes that cooperate to provide electric energy; thus, the fourth main group element of the hole-providing layer increases the hole Concentration, and reduce the inactivation phenomenon caused by Mg-H bonding, activate Mg to have the effective effect of acceptor, and then make the hole-providing layer have a higher hole concentration, thereby providing more holes Enter the light-emitting layer to increase the combination of electrons and holes, so that the semiconductor light-emitting element can exhibit a sufficiently low impedance, and then obtain good luminous efficiency.

Moreover, in order to solve the epitaxial dislocation phenomenon caused by lattice differences, a buffer layer can also be formed on the surface of the substrate, and the buffer layer is made of aluminum gallium nitride AlGa _y N _1-y , where 0<y <1.

Description of drawings

FIG. 1 is a schematic cross-sectional view of a nitride semiconductor structure provided by a preferred embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of a semiconductor light-emitting element made of a nitride semiconductor structure according to a preferred embodiment of the present invention.

Description of main component symbols:

1 Substrate 2 N-type semiconductor layer

21 N-type electrode 3 P-type semiconductor layer

31 P-type electrode 4 Light-emitting layer

5 Hole providing layer 6 P-type carrier blocking layer

7 N-type carrier blocking layer 8 Buffer layer

Detailed ways

The purpose of the present invention and its structural design and functional advantages will be described according to the following drawings and preferred embodiments, so as to have a more in-depth and specific understanding of the present invention.

First of all, in the description of the following embodiments, it should be understood that when it is indicated that a layer (or film) or a structure is disposed "on" or "under" another substrate, another layer (or film), or another structure , which can be "directly" located on other substrates, layers (or films), or another structure, or have more than one intermediate layer between them in an "indirect" manner. The location of each layer can be described with reference to the drawings.

Please refer to FIG. 1, which is a schematic cross-sectional view of a nitride semiconductor structure provided by a preferred embodiment of the present invention, which includes an N-type semiconductor layer 2 and a P-type semiconductor layer 3, between the N-type semiconductor layer 2 and the P-type semiconductor layer. A light-emitting layer 4 (active layer) is arranged between the P-type semiconductor layer 3, and a hole-providing layer 5 is arranged between the light-emitting layer 4 and the P-type semiconductor layer 3. The hole-providing layer 5 is indium gallium nitride In _x Ga _1-x N , where 0<x<1, ^the preferred value range of x is 0<x≤0.1; in addition, the hole supply layer 5 is doped with ^{the fourth} main group element (preferably carbon); in this embodiment, the N-type semiconductor layer 2 is an N-type GaN-based semiconductor layer, and the P-type semiconductor layer 3 is a P-type GaN-based semiconductor layer.

In addition, the above-mentioned hole providing layer 5 is doped with a P-type dopant (such as magnesium) with a concentration greater than 10 ¹⁸ cm ⁻³ , and the hole providing layer 5 preferably has a thickness of 1-100 nm.

Furthermore, the above-mentioned light-emitting layer 4 has a multiple quantum well structure (multiple quantum well, MQW); wherein, the multiple quantum well structure can be alternately composed of well layers (well) of InGaN and barrier layers (barrier) of GaN The stack is formed; and the energy gap (bandgap energy) of the hole providing layer 5 is greater than the energy gap of the well layer of the multiple quantum well structure, so that holes can enter the well layer of the multiple quantum well structure to increase electrons and holes Combined with the probability, the luminous efficiency is further improved.

In addition, a P-type carrier blocking layer 6 may be disposed between the hole supply layer 5 and the P-type semiconductor layer 3, and the P-type carrier blocking layer 6 is made of a material having an energy gap larger than that of the light-emitting layer 4; In the embodiment, it is P-type aluminum gallium nitride (P-AlGaN), so as to prevent electrons from escaping into the P-type semiconductor layer 3, which has the function of slowing down the electron movement rate and increasing the time of staying in the light-emitting layer 4; An N-type carrier blocking layer 7 may also be disposed between the layer 4 and the N-type semiconductor layer 2, and the N-type carrier blocking layer 7 is made of a material having an energy gap higher than that of the light-emitting layer 4; in this embodiment , which is N-type aluminum gallium nitride (N-AlGaN), thereby preventing holes from escaping into the N-type semiconductor layer 2 .

When the nitride semiconductor structure according to the above embodiment is actually used, since the hole-providing layer 5 is doped with the fourth main group element at a concentration of 10 ¹⁷ -10 ²⁰ cm ^-3 , the fourth main group element is used to replace the pentavalent Nitrogen atom, thus one more positively charged hole, so that the hole supply layer can have a high hole concentration, the above-mentioned fourth main group element can be, for example, carbon (C), silicon (Si), germanium (Ge), Tin (Sn), lead (Pb), etc., among them, carbon is preferred, the reason is that in the process of epitaxy, carbon will react with hydrogen decomposed from ammonia gas to form a stable compound CH ₄ , and detach nitrogen compound semiconductor, so the content of H is reduced, and the situation of Mg-H bonding is also reduced, resulting in the effective effect of Mg having an ion state. Therefore, the hole-providing layer 5 can have a high hole concentration, thereby providing more The holes enter the light-emitting layer 4, thereby increasing the combination of electrons and holes.

Please refer to FIG. 2, the above-mentioned nitride semiconductor structure can be applied to semiconductor light-emitting elements. FIG. 2 is a schematic cross-sectional view of a semiconductor light-emitting element made of a nitride semiconductor structure according to a preferred embodiment of the present invention. Light emitting elements include at least:

a substrate 1;

An N-type semiconductor layer 2 configured on the substrate 1;

A light-emitting layer 4, which is configured on the N-type semiconductor layer 2; wherein, the light-emitting layer 4 has a multiple quantum well structure;

A hole supply layer 5, which is arranged on the light-emitting layer 4, the hole supply layer 5 is indium gallium nitride In _x Ga _1-x N, wherein 0<x<1, preferably 0<x≤0.1; moreover, The hole-providing layer 5 is doped with a fourth main group element (preferably carbon) at a concentration of 10 ¹⁷ -10 ²⁰ cm ^-3 ; wherein, the thickness of the hole-providing layer 5 is preferably 1-100 nm, and may be doped with A P-type dopant (for example, magnesium) with a concentration greater than 10 ¹⁸ cm ^-3 , and the energy gap of the hole-providing layer 5 is greater than that of the well layer of the multiple quantum well structure;

A P-type semiconductor layer 3 configured on the hole-providing layer 5;

An N-type electrode 21, which is configured on the N-type semiconductor layer 2 with an ohmic contact; and

A P-type electrode 31, which is configured on the P-type semiconductor layer 3 with ohmic contact; wherein, the N-type electrode 21 and the P-type electrode 31 cooperate to provide electric energy, and can be made of the following materials, but not limited to these materials: Titanium, aluminum, gold, chromium, nickel, platinum, and alloys thereof are well known to those skilled in the art, and are not the focus of the present invention, so they will not be repeated in the present invention.

In addition, a P-type carrier blocking layer 6 can be disposed between the hole supply layer 5 and the P-type semiconductor layer 3, and an N-type carrier blocking layer 7 can be disposed between the light-emitting layer 4 and the N-type semiconductor layer 2, and the N-type Both the carrier blocking layer 7 and the P-type carrier blocking layer 6 are made of materials with an energy gap higher than that of the light-emitting layer 4; moreover, in order to solve the epitaxial dislocation phenomenon caused by lattice differences, it is also possible to A buffer layer 8 is formed on the surface of the substrate 1, and the buffer layer 8 is made of aluminum gallium nitride _{AlGayN 1-y} , where 0<y<1.

Thus, it can be seen from the above description of the implementation of the nitride semiconductor structure that the semiconductor light-emitting element of the present invention reduces the inactivation phenomenon caused by the Mg-H bond through the dopant of the fourth main group element in the hole supply layer 5, so that Mg is activated to have an effective role as an acceptor, thereby making the hole-providing layer 5 have a high hole concentration, providing more holes to enter the light-emitting layer, and increasing the combination of electrons and holes, so that the semiconductor light-emitting element can exhibit a sufficiently low impedance, thereby obtaining good luminous efficiency.

To sum up, the nitride semiconductor structure and the semiconductor light-emitting device of the present invention can indeed achieve the expected use effects through the above-disclosed embodiments.

The drawings and descriptions disclosed above are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention; other equivalent changes or modifications made by those skilled in the art based on the features of the present invention are all It should be regarded as not departing from the protection scope of the present invention.

Claims (7)

1. a kind of nitride semiconductor structure, it includes a n type semiconductor layer and a p type semiconductor layers, are partly led in the N-type Body layer is configured with a luminescent layer with the P-type semiconductor interlayer, and the luminescent layer is configured with the P-type semiconductor interlayer Cave provides layer, and the hole provides layer close to the luminescent layer, and it is InGaN In that the hole, which provides layer,_xGa_1-xN, wherein 0<x<1, and the hole provides layer doped with a concentration of 10¹⁷-10²⁰cm^-3The 4th major element；

The hole provides layer and is configured with a p-type carrier barrier layer, and the p-type carrier obstructs with the P-type semiconductor interlayer Layer is as made by having the material for the energy gap for being higher than the luminescent layer；

4th major element is carbon；

The hole provides layer and is more than 10 doped with concentration¹⁸cm^-3P-type admixture；

The p-type admixture is magnesium.

2. nitride semiconductor structure as described in claim 1, wherein, the luminescent layer has multiple quantum well construction, and The hole provides energy gap of the energy gap more than the well layer of the multiple quantum well construction of layer.

3. nitride semiconductor structure as described in claim 1, wherein, the thickness that the hole provides layer is 1-100nm.

4. nitride semiconductor structure as described in claim 1, wherein, it is InGaN In that the hole, which provides layer,_xGa_1-xN, Wherein x is 0<x≤0.1.

5. nitride semiconductor structure as described in claim 1, wherein, the luminescent layer is matched with the N-type semiconductor interlayer A N-type carrier barrier layer is equipped with, and the N-type carrier barrier layer is made by the material with the energy gap for being higher than the luminescent layer Into.

6. nitride semiconductor structure as described in claim 1, wherein, the luminescent layer is matched with the N-type semiconductor interlayer A N-type carrier barrier layer is equipped with, and the N-type carrier barrier layer is made by the material with the energy gap for being higher than the luminescent layer Into.

7. a kind of semiconductor light-emitting elements, including at least has：

One substrate；

One n type semiconductor layer is configured on the substrate；

One luminescent layer is configured on the n type semiconductor layer；

One hole provides layer, is configured on the luminescent layer, and the hole provides layer close to the luminescent layer, and the hole Offer layer is InGaN In_xGa_1-xN, wherein 0<x<1, and the hole provides layer doped with a concentration of 10¹⁷-10²⁰cm^-3's 4th major element；4th major element is carbon；The hole provides layer and is more than 10 doped with concentration¹⁸cm^-3P-type mix Matter；The p-type admixture is magnesium；

One p type semiconductor layer is configured at the hole and provides on layer；

One p-type carrier barrier layer is configured at the hole and provides layer and the P-type semiconductor interlayer, and the p-type carrier hinders Interlayer is as made by having the material for the energy gap for being higher than the luminescent layer；

One N-type electrode is configured at Ohmic contact on the n type semiconductor layer；And

One P-type electrode is configured at Ohmic contact on the p type semiconductor layer.