Etching SiO2 with HF/pyridine-supercritical carbon dioxide solutions and resultant interfacial electronic properties

Abstract

Silicon dioxide (SiO2) films grown on single crystal Si in high temperature O2 were etched using nonaqueous HF/pyridine solutions in supercritical CO2. The etch rate of SiO2 films were studied in the solutions with HF concentration up to 1000μM at 1.38×107Pa and at 35, 45, and 55°C. Capacitance versus voltage, conductance versus voltage, and leakage current measurements were performed on capacitor structures fabricated after SiO2 regrowth on completely etched Si surfaces. The electronic results revealed no systematic differences of etched and unetched samples with various etch times concentrations and that the Si–SiO2 interface of completely etched samples was comparable to the unetched control sample in terms of interface electronic charge and states and leakage current.