CN103779185A - Self-stripping method for growing GaN thick film - Google Patents

Abstract

The invention discloses a method for growing a self-stripping semiconductor alloy thick film, comprising the following steps: step 1: depositing a layer of semiconductor alloy thin film on a substrate; step 2: growing a sacrificial layer on the semiconductor thin film; step 3: On the sacrificial layer, a semiconductor alloy thick film is grown; step 4: when the thickness of the semiconductor alloy thick film reaches a certain thickness, the semiconductor alloy thick film is peeled off from the sacrificial layer to become a self-supporting semiconductor alloy thick film. The invention avoids the current commonly used laser stripping and the laser physical damage caused by it, and the sacrificial layer relaxes the stress accumulated by the heterogeneous epitaxy, and avoids the cracking of the epitaxial thick film.

Description

A self-stripping method for growing GaN thick film

technical field

The invention relates to a self-stripping method for growing a GaN thick film by using carbon nanotube arrangement as a sacrificial layer, and belongs to the technical field of semiconductors.

Background technique

The third-generation semiconductor material represented by GaN is a new type of semiconductor material that has received much attention internationally in the past decade. It has broad application prospects in white light LEDs, short-wavelength lasers, ultraviolet detectors, and high-temperature and high-power devices. However, due to the special stability of GaN (melting point 2791K, melting pressure 4.5GPa), there is a lack of natural GaN bulk single crystal materials in nature, and the current main work is carried out on heterogeneous epitaxy on sapphire, SiC, Si and other substrates. Due to the lattice mismatch and thermal mismatch between GaN and the substrate, there is a high dislocation density in the heteroepitaxial GaN film, and the dislocations will form non-radiative recombination centers and light scattering centers, which greatly reduce the luminous efficiency of optoelectronic devices. In addition, heteroepitaxy also brings some other problems to the device, such as difficult cleavage and poor heat dissipation. Therefore, the development of a GaN substrate material process suitable for large-scale manufacturing is crucial to the development of the GaN semiconductor device industry. Among the GaN substrate growth technologies, hydride vapor phase epitaxy (HVPE) has become a breakthrough technology for GaN substrates due to its high growth rate (up to 800 μm/h or more), low cost, large-area growth and good uniformity. preferred. HVPE grows GaN substrates, usually epitaxial 0.5-1mm thick film on substrates such as sapphire or gallium arsenide, and then removes the substrate by laser lift-off, grinding or etching, and finally polishes the obtained GaN to form So-called free-standing GaN substrates. However, due to the heteroepitaxy process, the lattice mismatch and thermal mismatch between the GaN epitaxial thick film and the substrate used caused the epitaxial film to crack, warp, etc. These problems led to low yield. The main reason for the expensive substrate.

Contents of the invention

The purpose of the present invention is to use carbon nanotube arrangement as a sacrificial layer to grow GaN thick film by HVPE. And this layer of GaN thick film can be peeled off from the base material, avoiding the more commonly used laser peeling and the laser physical damage it brings. More importantly, the sacrificial layer relaxes the stress accumulated by the heteroepitaxial layer and avoids cracking of the epitaxial thick film.

The invention discloses a method for growing a self-stripping semiconductor alloy thick film, which comprises the following steps:

Step 1: Deposit a layer of semiconductor alloy thin film on the substrate;

Step 2: growing a sacrificial layer on the semiconductor thin film;

Step 3: growing a semiconductor alloy thick film on the sacrificial layer;

Step 4: When the thickness of the semiconductor alloy thick film reaches a certain thickness, the semiconductor alloy thick film is peeled off from the sacrificial layer to become a self-supporting semiconductor alloy thick film.

The present invention uses carbon nanotubes as a sacrificial layer to grow a thick GaN film, and utilizes the thermal mismatch to realize a complete self-stripping GaN substrate during the cooling process with the help of the formed porous structure, thereby avoiding the current commonly used laser stripping and its laser physical damage. More importantly, the sacrificial layer relaxes the stress accumulated by the heteroepitaxial layer and avoids cracking of the epitaxial thick film.

Description of drawings

Fig. 1 is a schematic diagram of the epitaxy of growing a self-stripping GaN thick film using a carbon nanotube array as a sacrificial layer in the present invention.

Fig. 2 is a schematic diagram of the self-stripping process of growing a GaN thick film with a carbon nanotube array as a sacrificial layer in the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

Please refer to Fig. 1 to Fig. 2, the present invention provides a kind of method that uses carbon nanotube arrangement as sacrificial layer growth self-stripping GaN thick film, comprises the following steps:

Step 1: Take a substrate 11 and deposit a thin layer of GaN on the substrate 11 by MOCVD, called MOCVD GaN12. The substrate 11 material can be glass, sapphire, Si, ZnO, AlN, SIC, GaN, GaAs, LiAlO ₂ , or other III/V, IV/VI binary, ternary and quaternary compound semiconductor alloy substrate materials , Also includes metallic materials such as Cu and non-metallic materials such as quartz. The thickness of MOCVD GaN12 is 1-100 microns. The method of growing MOCVD GaN12 can also be the epitaxial growth technology of other GaN materials such as MBE growth technology.

Step 2: arrange the carbon nanotube array 13 on the MOCVD GaN12; wherein the carbon nanotube array 13 in step 2 can be a single layer or a multilayer array, wherein any angle can be formed between the multilayer stacks, and it can also be any arrangement. The preparation method of the carbon nanotube array 13 is a method of preparing carbon nanotubes at low temperature by chemical vapor deposition and other physical and chemical deposition methods. The carbon nanotubes in the carbon nanotube array 13 can be single-walled or multi-walled carbon nanotubes.

Step 3: On the carbon nanotube array 13, use HVPE to grow a GaN thick film, denoted as HVPE GaN thick film 14, wherein the growth method of the HVPE GaN thick film 14 can also be GaN epitaxial growth such as liquid ammonia method, MBE, MOCVD, etc. Other methods, see Figure 1.

Step 4: When the thickness of the HVPE GaN thick film 14 reaches 1 micron to 1 cm, it will be peeled off from the underlying material to become a self-supporting GaN substrate 21, as shown in FIG. 2 . After the self-stripping is completed, the thickness of the self-supporting GaN substrate 21 is between 1 micron and 1 cm.

The self-stripping technology of growing GaN thick film with carbon nanotube arrangement as a sacrificial layer can also be used to grow III/V, IV/VI binary, ternary and quaternary compound semiconductor alloy thick film materials. At the same time, here Carbon nanotube arrays can also be replaced by arrays of graphene material.

The present invention uses carbon nanotubes as a sacrificial layer to grow a thick GaN film, and utilizes the thermal mismatch to realize a complete self-stripping GaN substrate during the cooling process with the help of the formed porous structure, thereby avoiding the current commonly used laser stripping and its laser physical damage. More importantly, the sacrificial layer relaxes the stress accumulated by the heteroepitaxial layer and avoids cracking of the epitaxial thick film. The reason for its self-stripping is that the carbon nanotube array and the upper and lower GaN materials are in a non-close contact state. When the thick-film GaN reaches a certain thickness, it can form self-stripping due to its own stress.

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. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (9)

1. growth, from a method for stripping semiconductor alloy thick film, comprises the following steps:

Step 1: deposit layer of semiconductor alloy firm on substrate;

Step 2: the sacrifice layer of growing on described semiconductive thin film;

Step 3: on sacrifice layer, growing semiconductor alloy thick film;

Step 4: when the thickness of described semiconducting alloy thick film reaches certain thickness, described semiconducting alloy thick film is stripped down from sacrifice layer, become the semiconducting alloy thick film of self-supporting.

2. the method for claim 1, is characterized in that, described semiconducting alloy thick film is GaN thick film.

3. the method for claim 1, is characterized in that, described semiconducting alloy thick film is III/V family, IV/VI family binary, ternary and quaternary compound.

4. the method for claim 1, is characterized in that, described sacrifice layer is carbon nano pipe array or Graphene array, and this array is one or more layers array structure, is arbitrary arrangement between layers.

5. the method for claim 1, is characterized in that, the thickness of the film of semiconducting alloy described in step 1 is 1-100 micron, and growing method is MOCVD or MBE epitaxy technology.

6. the method for claim 1, is characterized in that, utilizes chemical vapour deposition technique low temperature to prepare sacrifice layer in step 2.

7. the method for claim 1, is characterized in that, the thickness of described semiconducting alloy thick film is between 1 micron to 1 centimetre, and growing method can be HVPE, liquid ammonia process for caustic soda purification, MBE or MOCVD.

8. the method for claim 1, is characterized in that, described substrate is glass, sapphire, Si, LiAlO ₂, or III/V family, IV/VI family binary, ternary and quaternary compound semiconductor alloy substrate material.

9. method as claimed in claim 4, is characterized in that, described carbon nano-tube is single wall or multi-walled carbon nano-tubes.

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