EFFECTS OF OXYGEN DOPING ON PROPERTIES OF MICROCRYSTALLINE SILICON FILM GROWN USING RAPID THERMAL CHEMICAL-VAPOR-DEPOSITION

An oxygen doped microcrystalline silicon (muc-Si) deposition process i s developed by mixing small amounts of nitrous oxide (N2O) with silane (SiH4) in a rapid thermal chemical vapor deposition (RTCVD) reactor. The effects of oxygen doping on the properties of RTCVD muc-Si films a re studied. Experimental results show that the RTCVD process provides high deposition rates for muc-Si and polycrystalline silicon (polySi) films at elevated deposition temperatures and pressures. The surface r oughness of the RTCVD muc-Si films can be significantly reduced compar ed to that of conventional LPCVD polySi films. Steep side walls can be realized due to the small grain size of the muc-Si films. The sheet r esistance of BF2 doped muc-Si films is slightly higher than that of BF 2 doped polySi films, whereas sheet resistances of P and As doped muc- Si films are much higher than those of the corresponding P and As dope d polySi films. Measurements of the catastrophic breakdown strength of metal-oxide-semiconductor (MOS) capacitors indicate that the quality of gate electrodes fabricated using muc-Si is improved relative to tha t of MOS capacitors fabricated using polySi gate electrodes.