Trap states in InAlN/AlN/GaN-based double-channel high electron mobility transistors

摘要

We present a detailed analysis of trap states in InAlN/AlN/GaN double-channel high electron mobility transistors grown by pulsed metal organic chemical vapor deposition. By frequency dependent conductance measurements, trap densities and time constants at both InAlN/AlN/GaN interfaces were determined. Two types of traps, with a high density of up to ～10~(14)cm~(-2)eV~(-1), were observed existing at the higher InAlN/AlN/GaN interface. On the other hand, the density dramatically decreased to ～10~(12)cm~(-2)eV~(-1) for traps located at lower InAlN/AlN/GaN interface on which a low-temperature grown GaN (LT-GaN) layer was deposited. Additionally, photo-assisted capacitance-voltage measurements were performed to estimate deep-level defects, yielding a low density of 1.79 × 10~(11)cm~(-2) acting as negative fixed charges at the LT-GaN and lower InAlN interface.