项目名称： 2英寸GaN衬底自分离过程中的三维应力控制及相关力学问题的研究

项目编号： No.61474003

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 吴洁君

作者单位： 北京大学

项目金额： 80万元

中文摘要： III族氮化物（又称GaN基）半导体是近年来国际上倍受重视的宽禁带半导体材料，具有优异的物理、化学性质。而GaN衬底的制备是实现III族氮化物半导体同质外延，大幅提高外延材料和器件质量的根本途径，谁先解决其中的关键科学和技术问题，将会占据未来III族氮化物半导体研究和产业化的战略制高点。本项目针对HVPE技术研制GaN衬底中的关键技术- - GaN厚膜与蓝宝石衬底的分离技术，探索并建立针对这种大失配非连续异质厚膜体系的三维应力模型，研究降温过程及自分离过程中GaN厚膜中三维应力产生及释放机制，三维应力控制下的不同裂纹形式，裂纹的起源、扩展或抑制湮灭的条件及规律。将相关力学问题的规律应用于GaN衬底自分离控制过程：利用有利形式裂纹平行于界面的扩展，同时抑制有害形式裂纹垂直于界面的扩展，从而导致2英寸GaN厚膜与蓝宝石衬底的完整自分离，获得2英寸GaN自支撑衬底。

中文关键词： GaN衬底；自分离；三维应力；氢化物气相外延技术；剥离

英文摘要： Recently, GaN-based materials have attracted much interest because of their wide range of applications, such as in light-emitting diodes and laser diodes. Unfortunately, a major issue in the production of blue-violet optoelectronic devices is the lack of a readily available substrate for the growth of GaN films of high crystallographic quality. Using the freestanding GaN substrates has many benefits, such as low dislocation density, high thermal conductivity and so on. However, fully separation of GaN from substrates is difficult because of bending and cracking due to the mismatch in the lattice constants and the thermal expansion coefficients. This project will focuse on the key technology in fabrication of GaN substrate-the separation of GaN film from the sapphire substrate, research and establish the three-dimensional stress model for GaN thick layer/sapphire system. Different types of fracture,including delamination and surface crack, will be studied. These models will be used in controlling the self-separation processes between GaN and sapphire substrate. Some useful methods of self-separation will be applied in fabrication 2 GaN substrate based on calculational and experimental results. In this work, we will obtained 2 GaN substrate with high qualities.

英文关键词： GaN substrates;self-separation;three-dimentional stresses;HVPE;peel off