Extremely low temperature formation of silicon dioxide on gallium arsenide

This article demonstrates the growth of silicon dioxide (SiO2) on a gallium arsenide (GaAs) substrate by use of the liquid phase deposition (LPD) method at extremely low temperature (∼40 °C). This method cannot only grow SiO2 but it can also obtain good quality and reliability due to the suppression of interdiffusion in such a low temperature process. The deposition rate of LPD-SiO2 on GaAs is up to 1265 Å/h. The refractive index of the LPD-SiO2 film on GaAs is about 1.42 with growth at 40 °C. When the LPD-SiO2 film on the GaAs substrate is used to fabricate a metal–oxide–semiconductor capacitor with a device area of 0.3 cm2, 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 proposed mechanism for the LPD of SiO2 on GaAs is also presented.