The effects of passivation and temperature on the strain of Al 0.22 Ga 0.78 N /GaN heterostructuers

作者：K. X. Zhang, Hangang Xie, J. N. Zhang, Dunjun Chen, G. D. Wang, Menglu Liu, A. M. Zhang · 发表于：Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 年份：2008 · DOI：10.1117/12.839301 · 研究领域：GaN-based semiconductor devices and materials、Metal and Thin Film Mechanics、Semiconductor materials and devices

The temperature dependencies of c-axis strain in Al 0.22 Ga 0.78 N/GaN heterostructure, with and without Si 3 N 4 passivation layer, were investigated at temperatures from room temperature (300K) to 813K using high resolution X-ray diffraction (HRXRD). The unpassivated Al 0.22 Ga 0.78 N layers total strain decrease is about 6% and 8% for the 50-nm- and 100-nm-thick Al 0.22 Ga 0.78 N layers, respectively, at whole temperature range from 300K to 813K in our measurements. The passivated Al 0.22 Ga 0.78 N layers total strain decrease is about 12% and 0% for the 50-nm- and 100-nm-thick Al 0.22 Ga 0.78 N layers, respectively, at the whole temperature range in our measurements. And at the common devices working temperature range, after passivating, the strain increase is about 4% and 8% of the 50-nm-thick Al 0.22 Ga 0.78 N and 100-nm-thick layers with temperature from 300K to 400K and 300K to 420K, respectively. The results indicate that a reasonable passivation layer is necessary to effectively impede strain decrease of Al x Ga 1-x N/GaN interface at the higher temperatures and that a passivation layer is conduce to increase c-axis strain at the working temperature range, hence passivation may improve the thermal stability and electricity characteristics of Al x Ga 1-x N/GaN heterostructures.