The manufacture method of heterogeneous buried laser device
Technical field
The invention belongs to the semiconductor device manufacture technology field, be meant the manufacture method of a kind of heterogeneous buried (BH) laser especially, it is that to stop its active layer of Metal Zn+ion pair in laser fabrication be the infringement of laser emitting region, plays a protective role.
Background technology
Along with the development of optical fiber communication technology, the arrival of photoelectronic industryization, the opto-electronic device product of all kinds structure is come out one after another, and device quality is also progressively improving.As the 1.3/1.5um laser of critical component in the optical fiber telecommunications system, indispensable especially as the signal transmission trunking.The device parameters index is when satisfying the communication system requirement, and the stability of device work is just particularly important.
The structure of present above-mentioned laser device roughly has two kinds, and a kind of is the ridge waveguide type structure, and is a kind of for burying the type structure in the plane.The ridge waveguide type structural advantages is that technology is comparatively simple, but that component characteristic parameter is buried the type structure devices than the plane is inferior slightly, and efficient is lower during the coupling encapsulation.And every characterisitic parameter that the type structure is buried on the plane is all comparatively desirable, and it is easy to the coupling encapsulation, and efficient is very high, and shortcoming is exactly a device aging life-span instability.So solving the stability of burying the type device architecture in the plane is the problem that we must consider.
Usually people etch micron order active layer stripe shape table top by the photoetching way after passing through MOCVD growing technology growth active layer on the material surface; Around micron order stripe shape table top, bury growth earlier with MOCVD and mix the N-InP layer that antimony is mixed in the P-InP layer regrowth of Zn, form reverse PN junction as current-limiting layer; By the cover lithography that the N-InP layer etching of micron order active layer stripe shape table top is most again; At last, mix the P-InP current injection layer of Zn+ ion with MOCVD growth 2um thickness.But around the micron order stripe shape table top during growth regulation one deck p-InP, (111) face of doping of Zn+ion pair micron order table top both sides active layer, particularly there is very large infringement effect at (111) In interface, and then the core that influences device is active layer, becomes the key factor that influences chip operation stability.
Summary of the invention
The object of the invention is to provide a kind of heterogeneous buried (BH) manufacture method of laser, and the infringement that it can stop its active layer of Metal Zn+ion pair plays a protective role to active area.
The invention provides a kind of manufacture method of heterogeneous buried laser device, comprise the steps:
Step 1: the active layer of on substrate, growing, as the emitter region of Laser Devices;
Step 2: at the superficial growth SiO of active layer
2Layer shields in etching and MOCVD growth course;
Step 3: photoetching, at SiO
2The both sides of laminar surface are with SiO
2Layer and active layer etch away, and form micron order ridge table top in the middle of making, and the active layer after the photoetching becomes the emitter region of Laser Devices;
Step 4: use the MOCVD technology, the eigen I nP layer of growing successively in the both sides of ridge table top, reverse P-InP junction current limiting layer and N-InP junction current limiting layer make on the ridge table top and form raceway groove;
Step 5: remove the SiO on the ridge mesa surfaces
2Layer;
Step 6: use the MOCVD technology, in raceway groove, remove SiO
2Reach the superficial growth P-InP current injection layer of N-InP junction current limiting layer on the ridge table top of layer, finish the making of device.
Wherein step 2 is described at active layer superficial growth SiO
2Layer is to adopt the growth of PECVD equipment, SiO
2The thickness of layer is 90-110nm.
Wherein the width of the described ridge table top that etches of step 3 is 1.5um-2.0um; The ridge platform and etching depth arrive in the substrate, distance is in the 1um.
The step that wherein also comprises a corrosion in step 3 photoetching, it is to adopt the saturated water zero degree corrosion 15s that smells.
Wherein the thickness of the described eigen I nP layer of step 4 is 0.8um-1.0um; The thickness of P-InP layer 50 is 0.8um-1.0um; The thickness of N-InP layer 60 is 0.8um-1.0um.
Wherein the thickness of the P-InP current injection layer in the step 6 is 2-3um.
Description of drawings
For further specifying technical characterictic of the present invention, in conjunction with the following drawings, the present invention is done a detailed description, wherein:
Fig. 1 (a) to Fig. 1 (f) be flow chart of the present invention;
Embodiment
See also Fig. 1 (a) to shown in Fig. 1 (f), the invention provides a kind of manufacture method of heterogeneous buried laser device, comprise the steps:
Step 1: growth active layer 20 on substrate 10, with the emitter region of MOCVD technology growth active layer 20 as Laser Devices, wavelength is generally 1.3um or 1.5um; Shown in Fig. 1 (a).
Step 2: at the superficial growth SiO of active layer 20
2Layer 30 shields in etching and MOCVD growth course; Described at active layer 20 superficial growth SiO
2Layer 30 is to adopt the growth of PECVD equipment, SiO
2The thickness of layer 30 is 90-110nm; SiO
2Thickness want evenly, unsuitable blocked up.Shown in Fig. 1 (b).
Step 3: photoetching, at SiO
2The both sides on layer 30 surface are with SiO
2Layer 30 and active layer 20 etch away, and form micron order ridge table top in the middle of making, and the active layer 20 after the photoetching becomes the emitter region of Laser Devices; Adopt conventional photoetching process exposure to produce photoresist mask stripe shape, with HF series corrosive liquid corrosion SiO
2, the width of the ridge table top that etches is 1.5um-2.0um; Glued membrane is washed with acetone; Utilize reactive ion (RIE) technology etching ridge table top, the degree of depth arrives in the substrate 10, and distance is in the 1um; The step that also comprises a corrosion, it is to adopt the saturated water zero degree corrosion 15s that smells, and etches the damage that ridge table top side is brought in order to reduce.Shown in Fig. 1 (c).
Step 4: use the MOCVD technology, the eigen I nP layer 40 of growing successively in the both sides of ridge table top, reverse P-InP junction current limiting layer 50 and N-InP junction current limiting layer 60 make and form raceway groove 70 on the ridge table top; The thickness of described eigen I nP 40 is 0.8um-1.0um; The thickness of P-InP layer 50 is 0.8um-1.0um; The thickness of N-InP layer 60 is 0.8um-1.0um; The reverse breakdown voltage that growth N/P-InP layer forms is the bigger the better, and electric current is the smaller the better, shown in Fig. 1 (d).
Step 5: remove the SiO on the ridge mesa surfaces
2Layer 30; Shown in Fig. 1 (e).
Step 6: use the MOCVD technology, in raceway groove 70, remove SiO
2Reach the superficial growth P-InP current injection layer 80 of N-InP junction current limiting layer 60 on the ridge table top of layer 30, the thickness of this P-InP current injection layer 80 is 2-3um, makes the resistance that forms P-InP layer passage the smaller the better.Finish the making of device.Shown in Fig. 1 (f).
Case study on implementation
With wavelength 1.5um Laser Devices structural design is example, utilizes the manufacture method of the present invention a kind of heterogeneous buried (BH) laser.The InP base of selecting laser emission wavelength 1.5um for use is as material.
1, growth active layer 20 on substrate 10, with the emitter region of MOCVD technology growth active layer as Laser Devices, wavelength is 1.5um.
2, growth SiO
2Layer 30: with PECVD equipment growth SiO
2The about 90-110nm of thickness.SiO
2The thickness of layer 30 is wanted evenly, and is unsuitable blocked up.
3, photoetching corrosion micron order table top: select S9912 eurymeric photoresist for use, adopt 300um cycle 1.5um stripe shape photolithography plate, expose with KarlSuss, after the 300um cycle 1.5um adhesive tape of developing, sample is put into 110 degree baking ovens decide film, will expose to SiO with HF again
2Corrosion to the greatest extent, with acetone remove photoresist clean after, just obtained the SiO of the wide 1.5um of bar of cycle 300um
2Stripe shape.With reactive ion (RIE) lithographic technique etching depth is the stripe shape table top of 1um, gets final product with the saturated water zero degree corrosion 15s that smells at last, and purpose is to remove the damage that reactive ion (RIE) etching is brought.
4, MOCVD buries growth eigen I nP layer 40, P-InP layer 50, N-InP layer 60 current-limiting layer earlier, forms raceway groove 70 on the ridge table top.At first with the eigen I nP resilient coating of MOCVD growth 1um thickness, its thickness is a little more than mesa top; Afterwards the growth about 1um thickness the P-InP layer of mixing Zn; At last the growth about 1um thickness doping N-InP layer.The reverse breakdown voltage that its N/P-InP layer forms is the bigger the better, and electric current is the smaller the better.
5, remove material surface SiO
2Layer 30 generally removes material surface SiO with HF series corrosive liquid
2
6, MOCVD growth P-InP current injection layer, MOCVD growth 2um thickness is mixed the P-InP layer of Zn.The resistance of the P-InP layer passage of its formation is the smaller the better.
The above; only be the embodiment among the present invention, but protection scope of the present invention is not limited thereto, anyly is familiar with the people of this technology in the disclosed technical scope of the present invention; the conversion that can expect easily or replacement all should be encompassed in of the present invention comprising within the scope.Therefore, protection scope of the present invention should be as the criterion with the protection range of claims.