CN103956417A - Method for preparing non-polar surface or semi-polar surface single crystal semiconductor self-supporting substrate - Google Patents

Abstract

A method for preparing a non-polar surface or semi-polar surface single crystal semiconductor self-supporting substrate, comprising: taking a substrate; growing a layer of zinc oxide crystal layer on the substrate as a sacrificial layer; A semiconductor support layer is grown at low temperature; a semiconductor single crystal epitaxial layer is grown on the surface of the semiconductor support layer. During the growth process, the zinc oxide in the zinc oxide crystalline layer is decomposed, and the semiconductor support layer and the semiconductor single crystal epitaxial layer Separation, the semiconductor support layer and the semiconductor single crystal epitaxial layer are semiconductor crystal layers; the semiconductor support layer of the semiconductor crystal layer is removed by mechanical polishing to obtain a semiconductor single crystal epitaxial layer, and the semiconductor single crystal epitaxial layer is non-polar The self-supporting substrate of single crystal semiconductor on the surface or semi-polar surface is completed. The invention has the advantages of low cost and large size.

Description

Method for preparing non-polar surface or semi-polar surface single crystal semiconductor self-supporting substrate

technical field

The invention relates to the field of semiconductor materials, in particular to a method for preparing a nonpolar surface or semipolar surface single crystal semiconductor self-supporting substrate.

Background technique

Gallium nitride (GaN) and aluminum nitride (AlN) light-emitting diodes (LEDs) with non-polar or semi-polar surfaces have become a research hotspot nowadays. The reason is that, on the one hand, non-polar surface and semi-polar surface materials do not have spontaneous polarization and piezoelectric polarization, which can avoid the quantum confinement Stark effect and improve the internal quantum efficiency of LEDs. On the other hand, since the light waves emitted by non-polar and semi-polar LEDs are polarized light, they can be directly used in the backlight of flat-panel displays, which greatly simplifies the design of backlighting for flat-panel displays, thus reducing the cost of device fabrication. complexity and reduce costs. However, the substrate problem is one of the main bottlenecks limiting the application of non-polar and semi-polar LEDs. Currently, heterogeneous substrates such as R-plane or M-plane sapphire are usually used to grow non-polar or semi-polar GaN and AlN materials, and heterogeneous epitaxy makes the crystal quality of epitaxial materials poor, and usually exists in the epitaxial film. High-density stacking faults. Therefore, homoepitaxy has become one of the breakthrough points that people are looking for at present.

At present, GaN substrates with non-polar or semi-polar surfaces on the market are mostly made of GaN ingots along the and The crystal face is obtained by cutting, but since the size of the GaN ingot prepared by the ammonothermal method and the high-pressure solution method is still very small, the size of the GaN substrate obtained by cutting is also very small. However, since the preparation technology of AlN crystal is not yet mature, there is no AlN substrate prepared by this method. Another method is to use hydride vapor phase epitaxy (HVPE) to first heterogeneously epitaxially grow thick film materials on such as R-plane or M-plane sapphire substrates or silicon carbide substrates, and then use reactive ion etching or laser lift-off technology The substrate is removed by the method of peeling off the substrate, so as to obtain a self-supporting GaN or AlN substrate with non-polar and semi-polar surfaces. However, this method for stripping the substrate not only has a complicated process, is not conducive to reducing the cost of the substrate, but also cannot perform stripping of a large-size substrate. Therefore, using a new method to avoid complex substrate lift-off techniques such as laser lift-off as much as possible, and to prepare large-scale self-supporting GaN and AlN substrates is the solution to the problem of gallium nitride (GaN) and GaN on non-polar or semi-polar surfaces. The crux of the problem for aluminum nitride (AlN) light-emitting diodes.

Contents of the invention

The main purpose of the present invention is to provide a method for preparing non-polar surface or semi-polar surface single crystal semiconductor self-supporting substrate, to solve the current low-cost, large-scale non-polar surface or semi-polar surface GaN and AlN self-supporting substrate. The current situation of the lack of supporting substrates further promotes the research and industrialization of non-polar or semi-polar light-emitting diodes (LEDs).

In order to achieve the above object, the technical solution of the present invention provides a method for preparing a non-polar surface or semi-polar surface single crystal semiconductor self-supporting substrate, comprising the following steps:

Step 1: Take a substrate, clean the surface, and place it in the growth chamber of the material growth equipment;

Step 2: growing a zinc oxide crystal layer on the substrate as a sacrificial layer;

Step 3: growing a semiconductor support layer at low temperature on the zinc oxide crystalline layer;

Step 4: Place the material with the zinc oxide crystal layer and the semiconductor support layer in the reaction chamber of the halide vapor phase epitaxy equipment, use hydrogen as the carrier gas and grow semiconductor single crystal epitaxy on the surface of the semiconductor support layer under high temperature conditions During the growth process, due to the etching effect of high temperature and hydrogen on the zinc oxide crystal layer, the zinc oxide in the zinc oxide crystal layer is decomposed, and the semiconductor support layer and the semiconductor single crystal epitaxial layer are separated from the substrate. The semiconductor support layer and the semiconductor single crystal epitaxial layer are semiconductor crystal layers;

Step 5: Remove the semiconductor support layer of the semiconductor crystal layer by mechanical polishing to obtain a semiconductor single crystal epitaxial layer, the semiconductor single crystal epitaxial layer is a single crystal semiconductor self-supporting substrate with a non-polar surface or a semi-polar surface , to complete the preparation.

The invention has the beneficial effects of providing a simple method for preparing a non-polar surface or semi-polar surface single crystal semiconductor self-supporting substrate, which saves complex substrate lift-off techniques such as laser lift-off techniques, and simplifies Improve the overall preparation process, improve the efficiency and yield of substrate preparation, and can solve the current situation of lack of low-cost, large-size non-polar or semi-polar GaN and AlN self-supporting substrates, thereby promoting non-polar or semi-polar Research and industrialization of semi-polar surface light-emitting diodes (LEDs).

Description of drawings

In order to further illustrate the specific technical content of the present invention, the following will be described in detail in conjunction with specific embodiments and accompanying drawings, wherein:

Fig. 1 is a preparation flow chart of the present invention;

Fig. 2 is a structural representation of the present invention;

3 is a schematic diagram of the separation of the semiconductor support layer 3 and the semiconductor single crystal epitaxial layer 4 from the substrate 1 after the zinc oxide crystalline layer 2 is etched away;

FIG. 4 is a schematic diagram of a semiconductor free-standing substrate obtained after removing the semiconductor support layer 3 .

Detailed ways

Please refer to Fig. 1, and in conjunction with referring to Fig. 2-shown in Fig. 4, the present invention provides a kind of method for preparing nonpolar surface or semipolar surface single crystal semiconductor self-supporting substrate, comprises the following steps:

Step 1: Take a substrate 1, clean the surface, and place it in the growth chamber of the material growth equipment. The substrate 1 is a non-polar surface or semi-polar surface substrate, and the material of the substrate 1 is the R surface Sapphire substrate, M surface sapphire substrate, surface SiC substrate or surface silicon carbide substrate; the material growth equipment is metal-organic chemical vapor deposition equipment or pulsed laser deposition equipment.

Step 2: growing a layer of zinc oxide crystal layer 2 on the substrate 1 as a sacrificial layer, the thickness of the zinc oxide crystal layer 2 is 100nm to 500nm;

The zinc oxide crystalline layer 2 can be prepared by metal-organic chemical vapor deposition technology. Before growing the zinc oxide crystalline layer 2, the substrate 1 is baked at 1100° C. for 20 minutes under nitrogen gas, and then nitrogen gas is used to The mixed carrier gas of oxygen and oxygen oxidizes the substrate for 3 minutes, and then grows a zinc oxide crystal layer 2 with a thickness of 100nm to 500nm at 500-750°C.

The zinc oxide crystalline layer 2 can also be prepared by pulsed laser deposition technology, and a zinc oxide crystalline layer 2 with a thickness of 100nm to 500nm is grown on the substrate 1 at 700-800°C;

Step 3: grow a layer of semiconductor support layer 3 on the zinc oxide crystal layer 2 at low temperature, the temperature when growing the semiconductor support layer 3 is lower than 800°C, so as to prevent the zinc oxide in the zinc oxide crystal layer 2 from decomposing during this process . The atmosphere for growing the semiconductor support layer 3 is nitrogen or argon, and cannot contain any components that corrode zinc oxide. The material of the semiconductor support layer 3 is gallium nitride or aluminum nitride, with a thickness of 2 μm to 50 μm, so as to ensure that the zinc oxide crystal layer 2 can support the upper semiconductor single crystal epitaxial layer 4 when decomposing during the high-temperature epitaxy process in step 4. role, so as not to break the semiconductor single crystal epitaxial layer 4.

The semiconductor support layer 3 can be prepared by metal organic chemical vapor deposition or pulsed laser deposition technology. If the metal organic chemical vapor deposition technique is adopted, the growth temperature of the semiconductor supporting layer 3 should be higher than 500° C., so as to ensure that the material of the semiconductor supporting layer 3 is a textured or single crystal material with a single orientation.

Step 4: Place the material with the zinc oxide crystalline layer 2 and the semiconductor support layer 3 in the reaction chamber of the halide vapor phase epitaxy equipment, use hydrogen as the carrier gas, and grow a semiconductor on the surface of the semiconductor support layer 3 under high temperature conditions In the growth process of the single crystal epitaxial layer 4, due to the etching effect of high temperature and hydrogen on the zinc oxide crystal layer 2, the zinc oxide in the zinc oxide crystal layer 2 is decomposed, so that the semiconductor support layer 3 and the semiconductor single crystal epitaxial layer 4 are separated from each other. The substrate 1 is separated, the semiconductor support layer 3 and the semiconductor single crystal epitaxial layer 4 are semiconductor crystal layers 10, and the growth temperature of the semiconductor single crystal epitaxial layer 4 is higher than 800°C to ensure that zinc oxide can be grown at this growth temperature Decomposition, the thickness of the grown semiconductor single crystal epitaxial layer 4 is 100-800 μm;

If the material of the semiconductor single crystal epitaxial layer 4 is gallium nitride material, its optimal growth temperature is 950-1100°C; if the material of the semiconductor single crystal epitaxial layer 4 is aluminum nitride material, its optimal growth temperature is The optimal growth temperature is 1200-1600°C.

If the zinc oxide crystalline layer 2 cannot be completely decomposed during the high-temperature growth process so that the semiconductor crystalline layer 10 cannot be separated from the substrate 1 during the growth process, the semiconductor crystalline layer 10 that is still bonded to the substrate 1 can be bonded after growth. Putting it into an acid solution to etch away the remaining zinc oxide, so as to realize the stripping of the semiconductor crystal layer 10 from the substrate 1 . The acid solution for etching zinc oxide may be dilute hydrochloric acid or dilute sulfuric acid, but it must be ensured that the acid solution cannot react with the material of the semiconductor crystal layer 10 while removing the zinc oxide.

Step 5: Remove the semiconductor support layer 3 of the semiconductor crystal layer 10 by mechanical polishing to obtain a semiconductor single crystal epitaxial layer 4, the semiconductor single crystal epitaxial layer 4 is a single crystal semiconductor with a non-polar surface or a semi-polar surface The self-supporting substrate, the material of the non-polar or semi-polar single crystal semiconductor self-supporting substrate is gallium nitride or aluminum nitride, and the preparation is completed.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. a method of preparing non-polar plane or semi-polarity face single crystal semiconductor self-supported substrate, comprises the following steps:

Step 1: get a substrate, carry out after surface cleaning, be placed in the growth room of material growing device;

Step 2: at Grown one deck zinc oxide crystallizing layer as sacrifice layer;

Step 3: low-temperature epitaxy layer of semiconductor supporting layer on zinc oxide crystallizing layer;

Step 4: the material with zinc oxide crystallizing layer and semiconductor supporting layer is positioned in the reative cell of halide vapour phase epitaxy equipment, adopt hydrogen to do carrier gas and under hot conditions, superficial growth semiconductor monocrystal epitaxial loayer at semiconductor supporting layer, in growth course, due to the corrasion for zinc oxide crystallizing layer of high temperature and hydrogen, the zinc oxide of zinc oxide crystallizing layer is decomposed, make semiconductor supporting layer and semiconductor monocrystal epitaxial loayer and substrate separation, this semiconductor supporting layer and semiconductor monocrystal epitaxial loayer are crystal semiconductor layer;

Step 5: adopt the method for mechanical polishing, the semiconductor supporting layer of crystal semiconductor layer is removed, obtain semiconductor monocrystal epitaxial loayer, this semiconductor monocrystal epitaxial loayer is the single crystal semiconductor self-supported substrate of non-polar plane or semi-polarity face, completes preparation.

2. the method for preparing non-polar plane or semi-polarity face single crystal semiconductor self-supported substrate according to claim 1, wherein said substrate 1 is non-polar plane or semi-polarity face substrate, the material of substrate is R face sapphire Substrate, M face sapphire Substrate, face silicon carbide substrates or face silicon carbide substrates.

3. the method for preparing non-polar plane or semi-polarity face single crystal semiconductor self-supported substrate according to claim 1, wherein the thickness of zinc oxide crystallizing layer is 100nm to 500nm.

4. the method for preparing non-polar plane or semi-polarity face single crystal semiconductor self-supported substrate according to claim 1, wherein temperature during growing semiconductor supporting layer is lower than 800 ℃, and growth atmosphere is nitrogen or argon gas.

5. the method for preparing non-polar plane or semi-polarity face single crystal semiconductor self-supported substrate according to claim 4, wherein the material of semiconductor supporting layer is gallium nitride or aluminium nitride.

6. the method for preparing non-polar plane or semi-polarity face single crystal semiconductor self-supported substrate according to claim 5, wherein the thickness of semiconductor supporting layer is 2 μ m to 50 μ m.

7. the method for preparing non-polar plane or semi-polarity face single crystal semiconductor self-supported substrate according to claim 1, wherein the growth temperature of growing semiconductor epitaxial single crystal layer is higher than 800 ℃, to guarantee that zinc oxide can decompose under this growth temperature.

8. the method for preparing non-polar plane or semi-polarity face single crystal semiconductor self-supported substrate according to claim 7, wherein the thickness of the semiconductor monocrystal epitaxial loayer of growth is 100-800 μ m.

9. the method for preparing non-polar plane or semi-polarity face single crystal semiconductor self-supported substrate according to claim 1, wherein the material of the single crystal semiconductor self-supported substrate of non-polar plane or semi-polarity face is gallium nitride or aluminium nitride.