Method for separating nitride self-supporting substrate by utilizing stress gradient

Abstract

The invention provides a method for separating a nitride self-supporting substrate by utilizing stress gradient and relates to a nitride based photoelectric device. The method for separating the nitride self-supporting substrate by utilizing the stress gradient comprises the steps of 1 performing on first-principle theory method analog computation of GaN layer crystal; 2 performing sapphire substrate pre-treatment before sample preparation; 3 enabling a GaN buffer layer to grow; 4 preparing GaN epitaxial growth. By utilizing relation of separation energy and stress, special treatment is performed in a GaN epitaxial layer grown by adopting an HVPE method, and the stress gradient distribution is adjusted by effectively controlling the thickness of the GaN epitaxial layer, so that a self separation phenomenon of the GaN epitaxial layer with the critical thickness is achieved. An in-situ GaN self separation technology is achieved by regulating and controlling epitaxial growth parameters, GaN self separation can be finished while HVPE growth, and the method is simple, easy to operate and good in practicability.

Description

technical field [0001] The invention relates to a nitride-based optoelectronic device, in particular to a method for separating a nitride self-supporting substrate by using a stress gradient. Background technique [0002] In recent years, group III nitrides InN, GaN, and AlN have attracted much attention as wide-bandgap direct semiconductors, and GaN-based semiconductors have become the most potential and promising for development because of their superior thermal stability, chemical stability, and high thermal conductivity. Materials have been widely used in the preparation of light-emitting diodes, lasers and photodetectors. After decades of research, new breakthroughs have been made in nitride materials. However, heterogeneous growth is generally used in nitride films, which largely hinders the improvement of the quality of III-nitride crystals. The preparation of high-quality nitride epitaxial layers has become one of the key scientific issues and difficult problems for...

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Problems solved by technology

At the same time, high dislocation gallium nitride restricts the preparation of high crystal quality AlGaN epitaxial layers, these problems seriously restrict the further rapid development of the quality and performance of (Al)GaN-based heterostructures

[0004] In order to overcome a series of problems caused by heterogeneous growth, research work in recent years has reported that the buffer layer is used to reduce the strain, and the substrate lift-off technology (H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, Applied Physics Letters48,353(1986)), laser lift-off technology (Chinese patent 2005100952458), wet chemical etching (K.Y.Zang, D.W.C.Cheong, H.F.Liu, H.Liu, J.H.Teng, and S.J.Chua, Nanoscale Research Letters5, 1051(2010 )) and lateral epitaxial growth in stripe seeds to separate GaN from sapphire or silicon substrates and recently Kobayashi and his colleagues (Y. 2012)) Separated GaN is obtained by inserting hexagonal BN between sapphire and GaN through a micromechanical separation method. However, the above method is not only complicated, but also inevitably brings dislocations to the interface and even weakens the crystal quality.

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