Improvement of Atomic-Layer-Deposited Al2O3/GaAs Interface Quality through a Novel Sulfuration Method

Abstract

The absence of stable oxide/GaAs interface greatly holds back the step of GaAs-based MOSFETs fabrication. In this letter, we report on the chemical passivation of n-type GaAs surface by introducing a new sulfuration method. X-ray photon-electron spectroscopy (XPS) analyses indicate that most GaAs native oxides and elemental arsenic (As) can be more effectively removed by treating the GaAs surface in CH3CSNH2solution compared to the traditional (NH4)2S solution. Capacitance-Voltage characteristics of the CH3CSNH2treated MOS capacitors also presents reduced interfacial layer and equivalent oxide thickness which are well consisted with the conclusion obtained by XPS.