Effects of Deuterium on Low-Temperature Si Epitaxy by Photo-Chemical Vapor Deposition

Epitaxial Si films have been successfully grown by the photochemical vapor deposition process using the mixture of SiH4, SiH2F2and D2gases at temperatures from 200 to 475°C. Using H2as diluting gas, the epitaxial Si films were obtained at temperatures from 200 to 350°C. However, the upper limit of the growth temperature was raised about 100°C (from 350 to 475°C) by substituting D2for H2as the diluting gas. Surface morphology and crystallinity were also improved with D2. Furthermore, we carried out heavy phosphorous doping with D2and obtained a film with an electron concentration of 1×1021cm-3.