At present, most InAs/GaSb ll superlattices are grown on lattice matched GaSb substrates. However, due to the high price of GaSb substrate, the absence of semi-insulating substrate, and the complexity of the process, seeking to grow GaSb bulk materials on new substrates, such as GaAs substrate, has become a new technical route for many international research and development units to realize the growth of InAs/GaSb superlattice. In addition, GaAs-based p-GaSb/n-GaAs structure can realize high efficiency thermal photovoltaic cells, which is a research hotspot. So far, GaAs is the most mature material with the best crystal quality in compound semiconductors. Therefore, using GaAs as the substrate material for heteroepitaxial growth by various technologies is a very interesting research subject, and has great practical value. PAM-XIAMEN offers services for heteroepitaxial films growth, like hetero-epitaxial GaSb thin film on GaAs substrate listed below. For additional information about our products, please refer to https://www.powerwaywafer.com/products.html.
1. Specification of GaSb Heteroepitaxial Growth on GaAs Substrate
We can provide GaAs wafers which have an epitaxial layer of GaSb as follows:
GaSb epi layer on GaAs (PAM190403 – GASB):
Epi layer: Thikness 0.5 um. Un-doped, GaSb
Substrate: 2” semi-insulating GaAs substrate, resistivity >1E8ohm.cm
2. Improve GaSb Heteroepitaxial Thin-Film Growth on GaAs by Adding Buffer Layer
Although there is great practical value for growing GaSb hetero-epitaxial materials, the lattice mismatch between GaAs and GaSb is large (~7%). If GaSb is directly grown on GaAs substrate, a large number of defects and dislocations will be generated at the interface due to stress, which is difficult to grow high-quality epitaxial materials. In order to solve this problem, many growth methods have been adopted to alleviate lattice mismatch and achieve high-quality heteroepitaxy.
Therein, the growth buffer layer is one of the important means to alleviate the lattice mismatch. Generally, the buffer layer is a single-layer or multi-layer structure with a certain thickness. Its function is to suppress the stress generated by the mismatch between the substrate and the epitaxial layer in the buffer layer, and reduce the dislocation and defects generated by the large mismatch heteroepitaxy.
InAs, AlSb and GaSb materials are usually selected as buffer layers for GaSb heteroepitaxial growth. It’s studied that the structural characteristics of GaSb films on GaAs (001) substrate at low temperature with different buffer layers. The results show that AlSb or GaSb buffer layer is very useful for improving the quality of GaSb films grown on GaAs substrates.
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