Mechanisms of Silicon Dioxide Deposition from the Low Pressure Chemical Vapor Deposition of Diethylsilane/Oxygen Mixtures

Abstract

Studies of the gas‐phase products, silicon dioxide film properties, and kinetics of the diethylsilane/oxygen reaction under low pressure chemical vapor deposition (LPCVD), conditions in both packed and unpacked stirred flow reactors are reported. Effects of flow rate, reactant composition, pressure, and various additives (e.g., ethene, helium, toluene, methylchloride, and various peroxides) on the reaction products, product yields, and reaction rates confirm the free radical nature of the reaction and provide mechanistic interpretations for the “cutoff” and “start‐up” problems sometimes encountered in the film deposition process. Additions of free radical source molecules promote the reaction. Thus process temperatures substantially lower than normal (i.e., ) can be used in the LPCVD process without effecting either film quality or film deposition rate. This process temperature lowering was a main study objective. Best results, as judged by film quality and uniformity, were achieved by matching the LPCVD reactor residence time of the reaction mixture to the decomposition lifetime of the promoter. Effective process temperatures were 315°C with added, 270°C with added , and 250°C with added .