A mechanism for diborane induced selectivity loss in the chemical vapor deposition of silicon from SiH₂Cl₂

The interaction between B2H6 and SiO2 was investigated by soft x-ray photoemission. Thermally activated, autocatalytic dissociative chemisorption of B2H6 on SiO2 to form elemental films was discovered at temperatures exceeding 550°C. These surfaces are shown to be quite reactive towards SiH2Cl2. This process is thus a mechanism whereby the selectivity of chemical vapor deposition exhibited by SiH2Cl2 towards SiO2 can be rapidly degraded.