Deep levels in n-type AlGaN grown by hydride vapor-phase epitaxy on sapphire characterized by deep-level transient spectroscopy

摘要

Deep levels in unintentionally doped n-type Al_(0.09)Ga_(0.91)N and Al_(0.17)Ga_(0.83)N films grown on sapphire by hydride vapor-phase epitaxy were characterized using capacitance deep-level transient spectroscopy and were compared to the reported electron traps in GaN grown by various techniques. It was shown that at least three dominant deep levels exist in each sample. The Al mole fraction dependence of their activation energy suggested that each of these three levels has the same origin as the three dominant well known point-defect-related deep levels in GaN, respectively. It is thought that deep levels in GaN change their electric characteristics in low Al content AlGaN.