Plasma Hydrogenation Studies on Low-Temperature Mbe-Grown GaAs

Abstract

ABSTRACTThe effect of hydrogen plasma on the electrical properties of low-temperature-grown GaAs (LT-GaAs) is reported. LT-GaAs epitaxial layers, 2μm thick were grown on a <100>, semi-insulating GaAs (SI GaAs) substrate using molecular beam epitaxy (MBE) at 300°C. Some of the samples were annealed in- situ at 600°C for 1 hour. These LT-GaAs samples were then subjected to hydrogen plasma at 300°C in a parallel-plate, low-frequency (30KHz) system for varying times up to a maximum of 13 hours. Current through the LT-GaAs layers as a function of voltage (I-V), temperature (I-T), and time (I-t) was measured between two surface contacts formed by thermal evaporation of Au. Evidence of partical defect passivation found in the electrical characteristics of hydrogenated LT GaAs is presented. These include reduced current at low temperature (<210K) and reduced current activation energy at high temperature (>320K).