Low-temperature RPCVD of Si, SiGe alloy, and Si 1−yC y films on Si substrates using trisilane (Silcore ®)

Abstract

Si homo-epitaxial growth by low-temperature reduced pressure chemical vapor deposition (RPCVD) using trisilane (Si 3H 8) has been investigated. The CVD growth of Si films from trisilane and silane on Si substrates are compared at temperatures between 500 and 950 °C. It is demonstrated that trisilane efficiency increases versus silane's one as the surface temperature decreases. Si epilayers from trisilane, with low surface roughness, are achieved at 600 and 550 °C with a growth rate equal to 12.4 and 4.3 nm min −1, respectively. It is also shown that Si 1− x Ge x layers can be deposited using trisilane chemistry. The epitaxy of Si 1− y C y films as stressors source and drain is a promising way to improve the performances of n-type MOS devices. To take advantage of the tensile-strained Si 1− y C y films, the level of carbon into substitutional sites must be significant (⩾1%). Such levels of substitution require low growth temperatures (<650 °C) and high growth rates. Using trisilane and methylsilane gases, the highest substitutional carbon concentrations incorporated are 1.9% at 600 °C and 2.3% at 550 °C with growth rates equal to 20 and 7 nm min −1, respectively. Stress values of about few gigapascals have been measured on blanket Si 1− y C y films.