LPCVD of Tin Oxide from Tetramethyltin and Oxygen

Abstract
A low‐pressure chemical vapor deposition (LPCVD) process using tetramethyltin (TMT) and oxygen has been developed for preparing tin oxide films. Effects of temperature, pressure, and gas flow rates are systematically examined so that the wafer‐to‐wafer and within‐wafer thickness uniformities of less than 5% are obtained in the hotwall LPCVD reactor. Twenty‐three 75 mm or 100 mm wafers could be deposited during each run. Nominal deposition rate was 55 Å/min. Deposition rates as high as 120 Å/min was obtained at higher pressure and oxygen flow rates. Characterization results showed that the films were polycrystalline with a refractive index of between 2.00 to 2.10, a visible‐light transmission of 84%, and resistivity of 0.6 Ω‐cm.