Improvement of the Electrical Properties of the AlN/GaAs MIS System and Their Thermal Stability by GaAs Surface Stoichiometry Control

Abstract

The GaAs surface pre-treatment conditions for the MOCVD-AlN/GaAs MIS diodes are investigated. An AsH 3 pre-treatment just prior to the AlN deposition degraded the C-V characteristics of AlN/n-GaAs MIS diodes in the accumulation side. The characteristics and their stability were drastically improved by a pure H 2 pre-treatment at 500°C. It was confirmed that the free As at the interface generates surface states near the conduction band edge and that control of the surface stoichiometry and atomic structure is necessary to improve the MIS characteristics.