GaN‐to‐Si vertical conduction mechanisms in AlGaN/GaN‐on‐Si lateral heterojunction FET structures

The GaN‐to‐Si vertical conduction mechanisms on a low resistivity p‐type (111) Si substrate under high‐voltage operation are investigated using the temperature‐dependent high‐voltage C‐V characterization and device simulation. It is found the deep depletion and weak inversion in Si will result in a high electric field at the GaN/Si interface and induce the impact ionization of Si. The generated electrons will be injected into GaN buffer layer, fill in buffer traps and act as free carriers in GaN, eventually leading to considerable vertical leakage in the AlGaN/GaN‐on‐Si structures. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)