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 dioxi de (SiO2) on a gallium arsenide (GaAs) substrate using liquid phase deposit ion (LPD) at extremely low temperature (similar to 40 degrees C). In this p rocess, pretreatment of the wafer by ammonia solution with buffer kept at p H = 11-12 enriches OH radical formation on the GaAs surface, enhancing SiO2 deposition, providing good film quality, and reliability. The LPD SiO2 dep osition rate on GaAs substrate is up to 1303 Angstrom/h. The refractive ind ex of the LPD SiO2 film on GaAs substrate is about 1.423 with growth at 40 degrees 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) i s about 3.7 x 10(11) cm(-2) and the leakage current is 43.3 pA at -5 V. A m echanism for the deposition of silicon dioxide on a GaAs substrate is propo sed. (C) 1999 American Institute of Physics. [S0021-8979(99)04524-7].