Effect of a chemical modification on growth silicon dioxide films on gallium arsenide prepared by the liquid phase deposition method

Abstract

This article presents a chemical modification process to grow silicon dioxide (SiO2) on a gallium arsenide (GaAs) substrate using liquid phase deposition (LPD) at extremely low temperature (∼40 °C). In this process, pretreatment of the wafer by ammonia solution with buffer kept at pH=11–12 enriches OH radical formation on the GaAs surface, enhancing SiO2 deposition, providing good film quality, and reliability. The LPD SiO2 deposition rate on GaAs substrate is up to 1303 Å/h. The refractive index of the LPD SiO2 film on GaAs substrate is about 1.423 with growth at 40 °C. When the LPD SiO2 film on GaAs substrate is used to fabricate a metal–oxide–semiconductor capacitor, the surface charge density (Qss/q) is about 3.7×1011 cm−2 and the leakage current is 43.3 pA at −5 V. A mechanism for the deposition of silicon dioxide on a GaAs substrate is proposed.