阅读说明：本技术 一种高可靠性的应变量子阱激光器的外延片生长方法 (Epitaxial wafer growth method of high-reliability strain quantum well laser ) 是由 张帆 于 2019-11-21 设计创作，主要内容包括：本发明提供一种高可靠性的应变量子阱激光器的外延片生长方法,包括准备衬底；在衬底上依次生长Si缓冲层,Si过渡层,Si下限制层,下波导层,MQW有源区,上波导层,Zn上限制层,Zn帽层,Zn光栅层,Zn空间层,Zn梯度层,Zn接触层,Zn盖层。Si下限制层和Zn上限制层分别为上下δ掺杂限制层结构。与现有工艺相比,此δ结构可以保证一定程度上提升电子/空穴浓度,同时拉远了其限制层与有源区的界面接触,减少了Zn与Si向有源区的扩散,以此改善有源区的晶体质量,从而提升了应变量子阱激光器的可靠性。(The invention provides a method for growing an epitaxial wafer of a high-reliability strain quantum well laser, which comprises the steps of preparing a substrate; a Si buffer layer, a Si transition layer, a Si lower limiting layer, a lower waveguide layer, a MQW active region, an upper waveguide layer, a Zn upper limiting layer, a Zn cap layer, a Zn grating layer, a Zn spatial layer, a Zn gradient layer, a Zn contact layer and a Zn cap layer are sequentially grown on a substrate. The Si lower limiting layer and the Zn upper limiting layer are respectively of an upper delta doping limiting layer structure and a lower delta doping limiting layer structure. Compared with the prior art, the delta structure can ensure that the electron/hole concentration is improved to a certain degree, simultaneously, the interface contact between the limiting layer and the active region is further widened, the diffusion of Zn and Si to the active region is reduced, the crystal quality of the active region is improved, and the reliability of the strain quantum well laser is improved.)

1. A method for growing an epitaxial wafer of a high-reliability strain quantum well laser is characterized by comprising the following steps:

preparing a substrate;

growing a Si-doped InP buffer layer, a Si-doped (AlXGa) InyAs transition layer, a Si-doped InxAlAs lower limiting layer, (AlXGa) InyAs lower waveguide layer, (AlXGa) InyAs MQW active region, (AlXGa) InyAs upper waveguide layer, a Zn-doped InxAlAs upper limiting layer, a Zn-doped InP cap layer, a Zn-doped GaInxAsyP grating layer, a Zn-doped InP space layer, a Zn-doped GaxInAsyP gradient layer, a Zn-doped InGaAs contact layer and a Zn-doped InP cap layer on the substrate in sequence; the Si doped InxAlAs lower limiting layer and the Zn doped InxAlAs upper limiting layer are respectively of an upper delta doped limiting layer structure and a lower delta doped limiting layer structure, namely delta Si doped InxAlAs and delta Zn doped InxAlAs.

2. The method of claim 1, wherein the delta Si doped InxAlAs is formed by alternately growing 5-10 pairs of Si doped InxAlAs layers and undoped InxAlAs layers.

3. The method of claim 1, wherein the delta Zn graded InxAlAs is 5-10 pairs of undoped InxAlAs layers and Zn graded InxAlAs layers grown alternately.

4. The method for growing the epitaxial wafer of the high-reliability strained quantum well laser according to claim 1, wherein the step of growing the δ Si graded InxAlAs layer is as follows:

670-.

5. Epitaxial wafer growth of highly reliable strained quantum well lasers according to claim 1

The method is characterized in that the growth steps of the delta Zn graded InxAlAs layer are as follows:

670-.

6. The method for growing an epitaxial wafer of a highly reliable strained quantum well laser according to claim 1, wherein (A) isl_XThe growth of the Ga) InyAs MQW active region is 670-.

7. The method of claim 1, wherein the undoped (Al) is used for epitaxial wafer growth of a high-reliability strained quantum well laser_XGa)In_yThe As lower waveguide layer is split into four sections to grow, and the non-doped (Al)_XGa)In_yTMAl of As lower waveguide layer is reduced by a fixed ratio layer by layer, and TMIn is increased by the same fixed ratio layer by layer and is undoped (Al)_XGa)In_yAn As upper waveguide layer and said undoped (Al)_XGa)In_yThe As lower waveguide layer structure is in mirror image relationship.

8. The method as claimed in claim 1, wherein the growing of the Zn doped InP space layer comprises introducing TMIn and DEZn to ensure the doping concentration of 5-8e17cm^-2Growing a low-temperature Zn doped InP space layer under the condition to ensure that the doped layer is 5-8e17cm^-2Slowly raising the environment in the growth chamber to 650-670 ℃ and 100-200 mbar pressure to ensure that TMIn, PH3 and DEZn are introduced and the high-temperature Zn doped InP space layer is grown to ensure that the doping concentration thereof needs to be ensured>1e¹⁸cm^-2。

9. A method for growing an epitaxial wafer of a highly reliable strained quantum well laser according to any of claims 1-8, comprising the steps of:

1) preparing the substrate;

2) growing the Si doped buffer layer which is of a uniformly doped body structure, wherein the doping concentration of the Si doped buffer layer is 0.1-2e18cm-2;

3) growing the Si doped (AlXGa) InyAs transition layer which is in a uniformly doped body structure and has the doping concentration of 0.5-2e18cm-2;

4) growing the delta Si graded InxAlAs lower limiting layer;

5) growing the undoped (AlXGa) InyAs lower waveguide layer;

6) growing the (AlXGa) InyAs MQW active region;

7) growing the undoped (AlXGa) InyAs upper waveguide layer;

8) growing the delta Zn graded InxAlAs upper limiting layer;

9) growing the doped InP cap layer with the doping concentration of 5-8e17cm & lt-2 & gt;

10) growing the upper Zn doped GaInxAsyP grating layer with the doping concentration of 5-8e17 cm-2;

11) growing the Zn doped InP space layer;

12) growing the Zn doped GaxInAsyP gradient layer, wherein the gradient layer is divided into two layers, and the doping concentration of the two layers is more than 3e18 cm-2;

13) growing the Zn doped InGaAs contact layer, wherein the doping concentration of the Zn doped InGaAs contact layer is more than 1e19 cm & lt-2 & gt;

14) and growing the Zn doped InP cover layer, wherein the doping concentration of the Zn doped InP cover layer is 0.5-2e18cm & lt-2 & gt.

10. A method of growing an epitaxial wafer of highly reliable strained quantum well lasers according to any of claim 9, comprising the steps of:

1) preparing the substrate, placing the InP substrate in a growth chamber, heating to a growth environment of 710-730 ℃ in an H2 environment, baking for 10-20min under the pressure condition of 100mbar-200mbar, and introducing PH3;

2) growing the Si doped buffer layer, slowly reducing the environment in the growth chamber to a growth environment of 670 and 690 ℃ under the pressure condition of 100mbar-200mbar, and introducing TMIn and SiH4 to ensure that the doping concentration is 0.1-2e18cm-2;

3) growing the Si doped (AlXGa) InyAs transition layer, keeping the growth environment of 670-;

4) growing the delta Si doped InxAlAs lower limiting layer, keeping the growth environment of 670 ℃ and 690 ℃, keeping the pressure condition of 100mbar-200mbar, closing the TMGa, keeping the TMAl and the TMIn, firstly growing for 10-15s, then introducing the DEZn, and growing for 10-15s again under the same growth condition, thereby taking the structure as a periodic structure, growing for 5-10 cycles, and ensuring that the doping concentration is 1-3e18 cm-2;

5) growing the undoped (AlXGa) InyAs, keeping the growth environment of 670-;

6) growing the (AlXGa) InyAs MQW active region, keeping the growth environment of 670-;

7) growing the undoped (AlXGa) InyAs, keeping the growth environment of 670-690 ℃, keeping the pressure condition of 100mbar-200mbar, closing SiH4, introducing TMAl, TMIn and TMGa, wherein the upper waveguide layer grows in 4 sections, the TMAl component increases by 10 percent layer by layer from the increase, and the TMIn component decreases by the increase and decreases by 10 percent layer by layer;

8) growing the delta Zn graded InxAlAs upper limit layer, keeping the growth environment of 670 ℃ and 690 ℃, keeping the pressure condition of 100mbar-200mbar, closing the TMGa, keeping the TMAl and the TMIn, firstly growing for 10-15s, then introducing the DEZn, and growing for 10-15s again under the same growth condition, thereby taking the structure as a periodic structure, growing for 5-10 cycles, and ensuring that the doping concentration is 1-3e17 cm-2;

9) growing the doped InP cap layer, keeping the growth environment at 670-690 ℃ and the pressure condition of 100-200 mbar, closing TMGa, TMAl and AsH3, keeping TMIn and DEZn open, and introducing PH3 to ensure that the doping concentration is 5-8e17cm < -2 >;

10) growing the Zn-doped GaInxAsyP grating layer, cleaning the prepared product with the GaInxAsyP grating, putting the cleaned product into a reaction chamber, heating the product to a growth environment with the temperature of 710-730 ℃ under the environment of H2 and under the pressure condition of 100-200 mbar, baking the product for 7-13min, and introducing PH3 with the doping concentration of 5-8e17cm < -2 >;

11) growing the Zn doped InP space layer;

12) growing the Zn doped GaxInAsyP gradient layer, wherein the gradient layer is divided into two layers, the ambient temperature of a growth chamber at the temperature of 650-670 ℃ is kept, the pressure condition of 100mbar-200mbar is kept, TMGa and AsH3 are introduced, the layer is divided into two sections for growth, wherein x is more than or equal to 0.1 and less than or equal to 0.4, and the doping concentration is ensured to be more than 3e18 cm-2;

13) growing the Zn doped InGaAs contact layer, keeping the ambient temperature of a growth chamber at 650-670 ℃ and the pressure condition of 100-200 mbar, closing PH3, keeping introducing TMIn, TMGa and AsH3, and growing the InGaAs contact layer under the condition to ensure that the doping concentration of the InGaAs contact layer is more than 1e19 cm < -2 >;

14) and growing the Zn doped InP cover layer, keeping the environment temperature of a growth chamber at 650-670 ℃ and the pressure condition of 100mbar-200mbar, closing AsH3, TMGa, TMIn and DEZn, and then introducing TMIn, PH3 and DEZn to grow the InP cover layer.

Technical Field

The invention relates to the field of semiconductor lasers, in particular to a method for growing an epitaxial wafer of a high-reliability strain quantum well laser.

Background

In the semiconductor laser, because the Al (Ga) InP material DFB laser has the characteristics of single-mode output, narrow line width and the like, the laser is very suitable for long-distance and high-speed optical communication transmission, and is widely applied to the fields of optical fiber networks, PONs, data centers and the like. Since al (ga) InP materials have poor thermal conductivity and are prone to thermal saturation, which limits the high-temperature operating characteristics of conventional lasers, reducing the series resistance of al (ga) InP lasers has become a challenging issue, and increasing the electron/hole concentration in the confinement layer is an effective way to reduce the series resistance.

Disclosure of Invention

In order to achieve the purpose, the invention adopts the following technical scheme:

preparing a substrate;

growing a Si-doped InP buffer layer, a Si-doped (AlXGa) InyAs transition layer, a Si-doped InxAlAs lower limiting layer, (AlXGa) InyAs lower waveguide layer, (AlXGa) InyAs MQW active region, (AlXGa) InyAs upper waveguide layer, a Zn-doped InxAlAs upper limiting layer, a Zn-doped InP cap layer, a Zn-doped GaInxAsyP grating layer, a Zn-doped InP space layer, a Zn-doped GaxInAsyP gradient layer, a Zn-doped InGaAs contact layer and a Zn-doped InP cap layer on the substrate in sequence; the Si doped InxAlAs lower limiting layer and the Zn doped InxAlAs upper limiting layer are respectively of an upper delta doped limiting layer structure and a lower delta doped limiting layer structure, namely delta Si doped InxAlAs and delta Zn doped InxAlAs.

The growth method is to control the components and concentration of the corresponding gas, and the prior technical scheme which is the same as the invention is not described again.

Preferably, an InP substrate is prepared: and placing the InP substrate in a growth chamber, heating to 710-730 ℃ in an H2 environment, baking for 10-20min under the pressure condition of 100-200 mbar, and introducing PH3.

Preferably, the growth of the Si doped InP buffer layer: and slowly reducing the environment in the growth chamber to 670- & ltSUB & gt 690 ℃, introducing TMIn and SiH4 under the pressure condition of 100mbar-200mbar, and ensuring the doping concentration to be 0.1-2e18cm-2, so as to grow the Si doped InP buffer layer under the condition, wherein the Si doped buffer layer is of a uniformly doped body structure.

Preferably, growth of the Si doped (AlXGa) InyAs transition layer: keeping the growth environment at 670 and 690 ℃, closing PH3 under the pressure condition of 100mbar-200mbar, keeping TMIn introduction, simultaneously introducing AsH3, TMAl and TMGa, and growing a Si doped (AlXGa) InyAs transition layer with the doping concentration of 0.5-2e18cm-2 on the Si doped InP buffer layer grown in the 2 steps.

Preferably, the growth of the delta-Si doped InxAlAs lower limiting layer: keeping the growth environment at 670-690 ℃, closing TMGa under the pressure condition of 100mbar-200mbar, keeping TMAl, TMIn and SiH4 to be fed and firstly growing for 10-15s, then closing SiH4, and then growing for 10-15s under the same growth condition, so that the periodic structure is grown for 5-10 cycles, the doping concentration is ensured to be 0.5-2e18cm-2, delta doping is grown in a nun … u sandwich mode, n is a Si dopedInxAlAs layer, u is an undoped InxAlAs layer, and the last layer is an undoped InxAlAs layer.

Preferably, growth of the undoped (AlXGa) InyAs lower waveguide layer: keeping the growth environment of 670-.

Preferably, the growth of the (AlXGa) InyAs MQW active region: keeping the growth environment at 670-. The MQW active region is a strained quantum well, and is respectively a compressive strained QW layer and a tensile strained QB layer, the QW is an InyAs layer with a small forbidden band width (AlXGa) and is represented by compressive strain, the QB is an InyAs layer with a large forbidden band width (AlXGa) and is represented by tensile strain, the strain size and the strain form are realized by adjusting X, the QB layer is grown first, the QW layers are grown again and are accumulated in sequence, and the last QB layer is the QB layer.

Preferably, the growth of the upper waveguide layer of undoped (AlXGa) InyAs: keeping the growth environment of 670-; x is gradually changed to form a gradually changed band gap, and is divided into four sections to grow and correspond to X of the lower waveguide layer.

Preferably, the growth of the delta-Zn graded InxAlAs upper limiting layer: keeping the growth environment at 670-; and growing a delta-Zn graded InxAlAs upper limiting layer, wherein delta grading doping grows in a upu … p sandwich mode, p is a Zn graded InxAlAs layer, u is an undoped InxAlAs layer, and the last layer is a Zn graded InxAlAs layer.

Preferably, growth of the Zn graded InP cap layer: keeping the growth environment at 670-.

Preferably, a Zn graded GaInxAsyP grating layer is prepared with a doping concentration of 5 to 8e17cm "2, and includes 1) preparation of a GaInxAsyP grating, 2) preparation of a product of the prepared GaInxAsyP grating: cleaning the prepared product with the GaInxAsyP grating, putting the product into a reaction chamber, heating the product to a growth environment of 710-730 ℃ in an H2 environment, baking the product for 7-13min under the pressure condition of 100-200 mbar, and introducing PH3.

Preferably, the growth of the Zn sequenced InP space layer is prepared:

the method comprises the steps of 1) growing a low-temperature Zn-doped InP space layer, namely, slowly reducing the environment in a growth chamber to 650 ℃ at 630 DEG and 100mbar-200mbar, introducing TMIn and DEZn, ensuring the doping concentration of the TMIn and the DEZn to be 17cm-2 at 5-8e, growing the low-temperature Zn-doped InP space layer at the condition, ensuring the doping concentration of the low-temperature Zn-doped InP space layer to be 17cm-2 at 5-8e, and 2) growing the high-temperature Zn-doped InP space layer, namely, slowly increasing the environment in the growth chamber to 670 ℃ at 650 DEG, ensuring the introduction of the TMIn, the PH3 and the DEZn, and growing the high-temperature Zn-doped InP space layer at 1e18 cm-2.

Preferably, growth of the Zn graded GaxInAsyP gradient layer: keeping the environmental temperature of a growth chamber at 650 and 670 ℃ and under the pressure condition of 100mbar-200mbar, introducing TMGa and AsH3, and growing the layer in two sections, wherein x is more than or equal to 0.1 and less than or equal to 0.4, and ensuring that the doping concentration is more than 3e18cm < -2 >.

Preferably, the growth of the Zn doped InGaAs contact layer: keeping the ambient temperature of a growth chamber at 650 and 670 ℃ and the pressure of 100mbar-200mbar, closing PH3, keeping introducing TMIn, TMGa and AsH3, and growing an InGaAs contact layer under the conditions to ensure that the doping concentration of the InGaAs contact layer is more than 1e19 cm < -2 >.

Preferably, growth of the Zn graded InP cap layer: keeping the ambient temperature of the growth chamber at 650 and 670 ℃ and under the pressure condition of 100mbar-200mbar, closing AsH3, TMGa, TMIn and DEZn, and then introducing TMIn, PH3.DEZn to grow the InP cover layer.

The invention has the beneficial effects that:

1) the series resistance of the Al (Ga) InP material laser is reduced by improving the electron/hole concentration by adopting an upper delta pinning limiting layer structure and a lower delta pinning limiting layer structure, the interface contact between the limiting layer and the MQW active region is further widened, the diffusion of Zn and Si to the MQW active region is reduced, the crystal quality of the MQW active region is improved, and the reliability of the strained quantum well laser is improved.

2) The invention adopts a multilayer multi-component growth layer to improve the electron/hole concentration of the limiting layer and reduce the series resistance of the Al (Ga) InP material laser.

Detailed Description

The following further describes the specific embodiments of the present invention in combination with the technical solutions.