Substrate processing method for improving gallium nitride base material epitaxial layer quality

Abstract

The invention relates to a method of enhancing quality of GaN base material epitaxial film by patterning surface of the lase material. The steps are: before epitaxy growth, the direct process surface of base material of Al2O3, Si, GaAs etc. by pattening, to etch a group of parallel wedge slots in width 0.2-20 mum and depth 0.2-2 mum along a crystal orientation to form parallel bar graph on surface of base material, or to etch a other groups of wedge slots along a other crystal orientation on the base material to form diamond or rectangular graph, finally, cleaned dry patterned base material is send into epitaxying devie to be processed by programmed GaN film layer epitaxial growth. By the invention, dislocation density of epitaxial layer is reduced to order of magnitude 10 to the power 6 square cm. The invention method can be used for high quality film layer epitaxial growth of any base material in state that lattice of the epitaxial film layer material is obvious mismatchable.

Description

technical field [0001] The invention relates to a method for improving the quality of gallium nitride (GaN) base material epitaxial film layer by patterning the surface of substrate material. Especially when the crystal lattice of the substrate material and the epitaxially grown film material does not match obviously, the quality and performance of the epitaxial layer material can be significantly improved, and it is a substrate processing method that improves the structural integrity of the film layer. Background technique [0002] Among the rapidly developing semiconductor optoelectronic materials, the third-generation wide-bandgap semiconductor materials have attracted much attention in recent years. Especially III-V nitride materials, including GaN, AlN, InN, BN and their ternary and quaternary solid solutions, because of their large band gap (the band gap of the material can be modulated by adjusting the alloy composition) In the spectrum, it covers the entire band fro...

AI Technical Summary

Problems solved by technology

For the epitaxial growth material using this process method, due to the lateral growth above the mask layer, the dislocations generated by the interface are annihilated due to oblique convergence, so that the dislocation density above the mask layer is reduced, but the dislocation density of the film layer in the window area is not. In addition, the material grown in this way will inevitably have multiple interfaces, and voids and even cracks will appear at the junction of the film layers on the mask layer. These positions will become the accumulation area of ​​structural defects and significantly affect the quality of the material. quality

In addition, ELOG (lateral epitaxial growth technology) will inevitably bring impurity contamination and even damage to the material interface due to the need for photolithography and etching.