SOI基GaN生长中热应力的模拟计算分析

Model of thermal stress in GaN growth on SOI

通过分析SOI基GaN生长的机制,结合热膨胀系数不同而产生应力的原理,利用弹性力学原理,我们对已有的计算多层结构应力的模型进行了简化修改,得到了能够方便的计算SOI基GaN生长过程中的热应力分布的模型。对具体样品的模拟计算表明,GaN层中张应力的值约为0.5GPa,曲率半径为9.1m。SOI结构中SiO2埋层以及顶层硅厚度变化对GaN层的热应力影响很小,但是对SOI自身各层中应力影响较大。通过合理简化模型,我们分析了蓝宝石基以及SiC基GaN生长中的热应力的分布问题。

The thermal stress in GaN growth on SOI has been studied by modified G. H. Olsen ＆ M. Ettenberg model. The calculation results of a typical sample indicate that the stress in GaN on SOI is about 0.5GPa and the curvature radius is 9. 1m. After comparing the samples with different thickness of top Si and BOX layers, the results show that the thickness changes of each layer of SOI have little influence to the stress in GaN epi -layer, but much affect the stress in SOl structure itself. Further more, the simplified model can also explain the stress in GaN growth on SiC and sapphire substrates.