A method for preparing crack-free gan films on si substrates

Abstract

The invention provides a method for preparing a flawless GaN film on a Si substrate. The method includes the following steps that: a high-temperature AlN nucleation layer is grown on the Si substrate through adopting the metal organic chemical vapor phase epitaxy technology; three stress adjustment and control layers of which the Al components change gradiently are sequentially grown, wherein the first stress adjustment and control layer is a 5-cycle (30nm)AlxGa1-xN / (30nm)Al0.5Ga0.5N stress control layer, x being the Al component changing from 100% to 50%, the thickness of the insert layer being 0.3 micron, the second stress adjustment and control layer is a 4-cycle (25nm) AlyGa1-yN / (25nm)Al0.2Ga0.8N stress adjustment and control layer, wherein y being the Al component changing from 50% to 20%, the total thickness of the insert layer being 0.2 micron, the third stress adjustment and control layer is a 3-cycle (20nm)AlzGa1-zN / (20nm)GaN stress adjustment and control layer, z being the Al component changing from 20% to zero, the thickness of the insert layer being 0.12 micron; and a GaN layer is grown, the thickness of the film ranging from 1 to 1.5 microns; and finally, a flawless and high-quality Si substrate GaN film can be obtained. The method can be used for preparing AlGaN / GaN HEMT devices and the like.

Description

technical field [0001] The invention belongs to the technical field of semiconductor optoelectronics, and relates to a method for preparing a crack-free GaN thin film on a Si substrate, in particular to a method for preparing a crack-free GaN thin film on a Si substrate by inserting three layers of a stress-regulating layer whose Al composition gradually changes. method for cracked, high crystal quality GaN thin films. Background technique [0002] The large size and low price of Si substrate can reduce the cost of epitaxial growth. Compared with the insulating sapphire substrate with high hardness and poor thermal conductivity, the conductive Si substrate can effectively simplify the substrate thinning process and reduce the manufacturing process cost of optoelectronic devices. The difficulty of growing GaN on Si by metalorganic vapor phase epitaxy (MOVPE) lies in the fact that the lattice mismatch between the GaN wurtzite structure (0001) and the diamond structure Si (111...

AI Technical Summary

Problems solved by technology

[0006] However, the current mainstream insertion layer method cannot completely eliminate stress, and there are problems such as high defect density and warpage.

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