In situ strain measurements on GaN/AlGaN Schottky diodes with variable bias

Abstract

In situ high resolution x-ray diffraction measurements were performed on AlGaN/GaN Schottky diodes under variable bias conditions. The results show a linear variation in strain for the GaN channel with bias. For forward bias conditions, an in-plane tensile strain was observed, whereas for reverse bias a compressive strain was present. A discontinuity in the strain for the reverse bias measurements was also present because the width of the carrier depletion region exceeds the ∼2 μm GaN layer. The linear variation in the strain caused by variable bias may be due to a change in the piezoelectric charge at the AlGaN/GaN interface.