ROLE OF HYDROGEN DURING RAPID VAPOR-PHASE DOPING ANALYZED BY X-RAY PHOTOELECTRON-SPECTROSCOPY AND FOURIER-TRANSFORM INFRARED-ATTENUATED TOTAL-REFLECTION

The surface of boron-doped layers formed by rapid vapor-phase doping w as analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier-tran sform infrared-attenuated total reflection (FTIR-ATR), to determine th e role of the hydrogen carrier gas. Boron doping was carried out with a B2H6 source gas and a hydrogen carrier gas at 800 and 900 degrees C. A nitrogen carrier gas was also used for comparison. Using hydrogen c arrier gas, no evidence of boron segregation was observed in the XPS s pectra. FTIR-ATR analysis confirmed that the hydrogen termination of t he surface was maintained during doping. Using nitrogen carrier gas, l ayers that included segregated boron and silicon nitride were produced on the surface, which led to poor controllability of the boron concen tration. When a hydrogen carrier gas is used, the hydrogen termination should promote the surface migration of adsorbed species. The hydroge n carrier gas plays an important role in terminating the silicon dangl ing bonds, thus preventing excessive chemisorption of boron. (C) 1998 American Vacuum Society.