Structural and mechanical characterization of in-situ phosphorus-doped rapid transport low pressure chemical vapor deposition polycrystalline silicon films

Abstract

Rapid thermal low pressure chemical vapor deposition (RTLPCVD) of in-situ phosphorus-doped (P-doped) polycrystalline silicon (poly-Si) thin films was carried out in a cold-wall rapid thermal processing reactor. Doping was obtained by adding phosphine (PH 3=200 ppm) gas to silane (SiH 4/Ar=10%) at a process pressure of 2 mbar and a deposition temperature in the 600°C–850°C range. Microstructural and micromechanical properties of the deposited layers were investigated by means of grazing X-Ray Diffraction. It appeared, particularly, that in-situ P-doping is responsible for a small-grained and relatively high stressed structure. However, a post-deposition rapid thermal annealing seems to be beneficial for suitable mechanical applications of in-situ P-doped RTLPCVD poly-Si films.