Carbon‐Related Trap Dynamics in Semi‐Insulating Buffer Layer of GaN‐on‐Si Substrate

Semi‐insulating carbon‐doped GaN (C‐GaN) is essential for high‐power GaN‐on‐Si field effect transistors. Nevertheless, trap parameters and carrier dynamics in C‐GaN are controversial. This paper investigates transient characteristics relating to the traps in C‐GaN using back‐gating measurements, a useful method for researching variations of charge balance in buffer layers. The results show that positive charge accumulation is enhanced according to C doping, which is explained by a technology computer aided design simulation assuming the coexistence of donor and acceptor traps. Comparing the electric field profile between samples with different C concentrations, the role of C‐related traps is emphasized in enhancing vertical breakdown voltage and reliability during high‐voltage operation.