SUBATMOSPHERIC CHEMICAL-VAPOR-DEPOSITION OZONE TEOS PROCESS FOR SIO2 TRENCH FILLING/

Ozone/TEOS thermal chemical vapor deposition (CVD) has been investigat ed for SiO2 deposition bn Si, using a cold-wall research reactor equip ped to determine the effects of precursor concentration, deposition te mperature (300-500 degrees C), and pressure (30-200 Torr) on depositio n rates, etch rates, and step coverage in the regime of subatmospheric CVD (SACVD). Deposition rates first increase with substrate temperatu re then reach a maximum and finally decrease distinctly at higher temp eratures, with the latter reflective of reactant depletion in the gas phase. Wet etch rates decrease at higher deposition temperature and hi gher ozone/TEOS ratio, indicating improved film quality under these co nditions. Elevated deposition temperatures significantly improves step coverage in high-aspect-ratio trenches, but decreases deposition rate s. Deposition rates increase and then saturate with TEOS concentration , suggesting rate-limited behavior associated with lack of ozone. (C) 1995 American Vacuum Society.