DOPED SILICON-OXIDE DEPOSITION BY ATMOSPHERIC-PRESSURE AND LOW-TEMPERATURE CHEMICAL VAPOR-DEPOSITION USING TETRAETHOXYSILANE AND OZONE

Doped silicon oxides, phosphosilicate glass (PSG), and borosilicate glass (BSG) films were deposited using organic doping sources, trimethylphosphate for PSG films, and trimethylborate (TMB) and SiOB for BSG films. Deposition rate, doping level, film stress, etching rate by an aqueous HF solution, IR spectra and leakage current of the films were studied. In PSG deposition, a P2O5 content up to 6 mole percent (m/o), a deposition rate of as high as 150 nm/min and a film stress of less than 1 x 10(9) dyne/cm2 were obtained at 400-degrees-C. IR spectra showed that the PSG films were very stable even after boiling in water. Step coverage on aluminum steps was conformal or slightly nonconformal, and base material dependence of deposition rate was not observed, which would indicate a partial gas-phase reaction even in TEOS/O3 atmospheric pressure chemical vapor deposition. The extent of the nonconformality was much smaller than that of the silane-base PSG films. In BSG deposition a 200 nm/min deposition rate, a 1 x 10(9) dyne/cm2 film stress and a 14 m/o doping level were obtained at 400-degrees-C. The stress of films deposited at 400-degrees-C relaxed from tensile to compressive, 0.2 x 10(9) dyne/cm2. Leakage current of TMB/BSG films was very low, 15 nA/cm2, without annealing independent of doping level. Step coverage of both films was very conformal, however, base material dependence of deposition rate was observed. Both phenomena are the same as the USG case, but different from the PSG deposition. IR spectra of both films proved that the films were acceptably stable several days after deposition.