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

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 (Q_ss/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.