阅读说明：本技术 选择外延生长应变测量方法及量子阱激光器制作方法及量子阱激光器 (Selective epitaxial growth strain measurement method, quantum well laser manufacturing method and quantum well laser ) 是由 陈志标 于 2019-09-30 设计创作，主要内容包括：本发明公开了一种选择外延生长应变测量方法,包括如下步骤：1)在衬底上形成掩膜,在带有掩膜的衬底上选择外延生长材料；2)将选择外延生长区域以外的所有外延材料去除,将掩膜材料去除,仅仅剩下选择外延生长区域的材料；3)测量衬底上材料的应变,测量的应变为选择外延区域材料的应变。同时,提出一种利用该方法的选择外延生长量子阱激光器制作方法以及量子阱激光器。该方法能精确测量选择外延导致的应变的变化,从而为选择外延生长材料的表征提供一种低成本且精确的方法。且制作的量子阱激光器的性能良好。(The invention discloses a method for measuring selective epitaxial growth strain, which comprises the following steps: 1) forming a mask on a substrate, and selecting an epitaxial growth material on the substrate with the mask; 2) removing all epitaxial materials except the selective epitaxial growth region, removing the mask material, and only leaving the material of the selective epitaxial growth region; 3) the strain of the material on the substrate is measured, and the measured strain is the strain of the material in the selected epitaxial region. Meanwhile, a method for manufacturing the quantum well laser by utilizing the selective epitaxial growth method and the quantum well laser are provided. The method can accurately measure the change of strain caused by selective epitaxy, thereby providing a low-cost and accurate method for characterization of selective epitaxy growth materials. And the manufactured quantum well laser has good performance.)

1. A method for measuring selective epitaxial growth strain is characterized by comprising the following steps:

1) forming a mask on a substrate, and selecting an epitaxial growth material on the substrate with the mask;

2) removing all epitaxial materials except the selective epitaxial growth region, removing the mask material, and only leaving the material of the selective epitaxial growth region;

3) the strain of the material on the substrate is measured, and the measured strain is the strain of the material in the selected epitaxial region.

2. The method of claim 1, wherein: step 3) strain was measured by X-ray diffraction method.

3. The method of claim 1, wherein: and removing all epitaxial materials except the selective epitaxial growth region through a photoetching process, and removing the mask material to only leave the materials of the selective epitaxial growth region.

4. The method of claim 1, wherein: the mask material adopts SiO₂。

5. The method of claim 1, wherein: forming a mask on a substrate, comprising:

forming a plurality of pairs of strip-shaped masks on a semiconductor substrate, wherein no epitaxial material is deposited in the regions covered by the masks, and the regions not covered by the masks are normal epitaxial material growth regions; each pair of strip-shaped masks are arranged in parallel at intervals, and the gap area between each pair of strip-shaped masks is a selective epitaxial growth area.

6. A method for manufacturing a selective epitaxial growth quantum well laser is characterized by comprising the following steps:

1) measuring the strain of the lower waveguide layer material using the method of any one of claims 1 to 5, set to e;

2) forming a mask on a semiconductor substrate, and sequentially growing a buffer layer, a lower waveguide layer, a quantum well layer and an upper waveguide layer which are matched with the substrate on the substrate;

growing a lower waveguide layer comprising: growing a strain compensation lower waveguide layer with the strain quantity of-epsilon;

growing an upper waveguide layer comprising: growing a strain compensation upper waveguide layer with strain quantity of-epsilon;

3) and removing the mask layer and growing other layers of the laser.

7. The method of claim 6, wherein: growing a quantum well layer comprising: and growing a quantum well layer with the strain quantity increased by-epsilon relative to the design strain value.

8. The method of claim 6, wherein: the mask material adopts SiO₂。

9. A quantum well laser fabricated by the method of claim 6.

Technical Field

The invention relates to the field of information photoelectron, in particular to a MOCVD selective epitaxial growth strain measurement method, a selective epitaxial growth quantum well laser manufacturing method and a quantum well laser.

Background

Semiconductor lasers for optical communication are generally fabricated on group IIIV compound semiconductor substrates such as InP or GaAs, and in order to integrate more functional devices such as modulators, spot size converters, passive waveguides, etc. with the lasers, it is necessary to fabricate materials with different band gap wavelengths on the substrates by methods including selective epitaxial growth, butt-coupled growth, and different wavelength band gapsBonding materials with band gap wavelength to each other, and the like. The selective epitaxial growth generally forms masks with different shapes and sizes on the existing substrate, the area covered by the masks has no epitaxial material deposition, and the area covered by no masks is the normal epitaxial material growth area. Typical mask material is SiO₂The mask is generally in the shape of two parallel SiO₂The strips are separated by a certain gap, the growth rate of the gap area (selective epitaxial growth area) is higher than that of the planar area without mask coverage, so that epitaxial materials with different band gap wavelengths are formed on the gap area and the planar area.

Materials matched with a substrate and grown on a mask-free planar substrate generally introduce strain during selective epitaxial growth, because the growth rate is accelerated in a selective growth area, the diffusion lengths of source materials with different compositions are different, the growth rate of the source materials in the selective epitaxial area is increased by different times, and therefore the proportion of different material components is changed, and the strain is generated. Since lasers, modulators and the like are all manufactured in a selective epitaxial growth region, the change of strain can seriously affect the performance of the lasers, so a method for accurately measuring the strain of the selective epitaxial growth region is needed, because the width of the selective epitaxial region is generally dozens of microns, the traditional method is generally micro-zone X-ray diffraction [ Shigeru Kimura, et al, Jpn. J. Appl. Phys., Part2, vol.41, No.9A/B, 2002], the strain and the component of the material of the selective epitaxial region can be accurately measured by reducing an X-ray spot to the magnitude of dozens of microns and accurately irradiating the spot to the selective epitaxial growth region, and then the method needs precise and expensive X-ray diffraction equipment, the common X-ray diffraction method can accurately measure the strain, but the spot of the X-ray is too large and far exceeds the size of the selective epitaxial growth region, thus, the average strain and composition of the selective epitaxial region and the nonselective epitaxial region are measured by conventional X-ray, resulting in inaccurate measurements.

Disclosure of Invention

The invention aims to provide a novel method for measuring selective epitaxial growth strain aiming at the corresponding defects of the prior art, and simultaneously provides a method for manufacturing a selective epitaxial growth quantum well laser and a quantum well laser.

The purpose of the invention is realized by adopting the following scheme: the invention discloses a method for measuring selective epitaxial growth strain, which comprises the following steps:

1) forming a mask on a substrate, and selecting an epitaxial growth material on the substrate with the mask;

2) removing all epitaxial materials except the selective epitaxial growth region, removing the mask material, and only leaving the material of the selective epitaxial growth region;

3) the strain of the material on the substrate is measured, and the measured strain is the strain of the material in the selected epitaxial region.

Further, step 3) strain was measured by the X-ray diffraction method.

And removing all epitaxial materials except the selective epitaxial growth region through a photoetching process, and removing the mask material to only leave the materials of the selective epitaxial growth region.

Further, the mask material adopts SiO₂。

Further, forming a mask on the substrate, comprising:

forming a plurality of pairs of strip-shaped masks on a semiconductor substrate, wherein no epitaxial material is deposited in the regions covered by the masks, and the regions not covered by the masks are normal epitaxial material growth regions; each pair of strip-shaped masks are arranged in parallel at intervals, and the gap area between each pair of strip-shaped masks is a selective epitaxial growth area.

The invention discloses a method for manufacturing a selective epitaxial growth quantum well laser, which comprises the following steps:

1) measuring the strain of the lower waveguide layer material by using the method for measuring the selective epitaxial growth strain, and setting the strain as epsilon;

2) forming a mask on a semiconductor substrate, and sequentially growing a buffer layer, a lower waveguide layer, a quantum well layer and an upper waveguide layer which are matched with the substrate in lattice;

growing a lower waveguide layer comprising: growing a strain compensation lower waveguide layer with the strain quantity of-epsilon;

growing an upper waveguide layer comprising: growing a strain compensation upper waveguide layer with strain quantity of-epsilon;

3) and removing the mask layer and growing other layers of the laser.

Further, growing a quantum well layer comprising: and growing a quantum well layer with an increased strain amount of-epsilon relative to the design strain value. Generally, the strain of the waveguide layer should be zero to obtain better performance, but the epitaxy is selected to generate strain on the waveguide layer, so that the performance of the laser is cracked, and the strain change caused by epitaxy is compensated by adding an opposite strain in advance, so that the actual strain of the upper waveguide layer and the lower waveguide layer is zero, and the performance of the laser can be improved.

Further, the mask material adopts SiO₂。

The invention discloses a quantum well laser which is manufactured by adopting the manufacturing method of the selective epitaxial growth quantum well laser.

The invention has the advantages that: the invention forms a mask on a substrate, and selects an epitaxial growth material on the substrate with the mask; the epitaxial materials outside the selective epitaxial growth region are removed through a common photoetching process, and the strain of the selective epitaxial growth region can be measured by utilizing a traditional X-ray diffraction method, because the materials outside the selective epitaxial region are completely removed, the measured strain is the strain of the materials in the selective epitaxial region, so that expensive micro-area X-ray diffraction equipment is avoided, the method can accurately measure the change of the strain caused by selective epitaxy, and a low-cost and accurate method is provided for the characterization of the selective epitaxial growth materials.

Because the invention utilizes the method for manufacturing the selective epitaxial growth quantum well laser to form SiO on the semiconductor substrate₂The mask of (1) measuring the strain of the lower waveguide layer by the above method, assuming epsilon; formation of SiO on semiconductor substrate₂Growing a buffer layer, growing a strain compensation lower waveguide layer with a strain amount of-epsilon, growing a quantum well layer with an increased strain amount of-epsilon, and growingA strain compensation upper waveguide layer with a strain amount of-epsilon; SiO removal₂The laser is manufactured by selecting an epitaxial growth method, the upper waveguide layer and the lower waveguide layer are designed to have strain of-epsilon, the strain of the upper waveguide layer and the strain of the lower waveguide layer are increased by epsilon by selecting an epitaxial growth mechanism, and the comprehensive effect is that the strain of the upper waveguide layer and the strain of the lower waveguide layer are zero, so that the generation of material defects caused by large strain of the upper waveguide layer and the lower waveguide layer caused by selective epitaxy is avoided, and the manufactured quantum well laser has good performance.

Drawings

FIG. 1 is a diagram illustrating a selective epitaxy mask pattern according to a first embodiment of the present invention;

FIG. 2 is a schematic diagram of selecting an etching region after epitaxial growth in the first embodiment of the present invention (the oblique-line filled region is SiO)₂A mask region, wherein the black filling region is a selective epitaxial growth region);

FIG. 3 is an X-ray diffraction curve before and after etching according to a first embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of a MOCVD selective epitaxial growth material according to the present invention.

Detailed Description

The scheme of the invention is further explained by combining the drawings and the embodiment.