121 THE ELECTRICAL PROPERTIES OF SILICON OXIDE DEPOSITED BY REMOTE PLASMA ENHANCED CHEMICAL VAPOR DEPOSITION (RPECVD). SANG S. KIM, D. V. TSU AND G. LUCOVSKY North Carolina State University, Dept. of Physics, Raleigh, NC 27695-8202 ABSTRACT We have constructed an Ultra High Vacuum (UHV) multi- chamber system and have deposited 'gate quality' silicon dioxide by the remote plasma enhanced chemical vapor deposition (Remote PECVD) process at low substrate temperatures (T .400 C). Native oxides and other surface contaminants are removed under ultra high vacuum (UHV) conditions and the character of the semiconductor surface is determined prior to film deposition using in-situ Reflection High Energy Electron Defraction (RHEED). Measurents made on MOS structures of capacitance- voltage, current-voltage, field break-down, hysteresis, and mobile ion drift Wndicate that these films are 'comparable' to thermally (T >1100 C) grown oxides. The structural properties of the films arg studied by ir spectroscopy and ellipsometry. INTRODUCTION The deposition of silicon based dielectric thin films (silicon dioxide, nitride and oxynitride) at low Ts is currently of considerable interest because of the potential applications in a number of semiconductor device technologies. For example, for IC chip passivation, inter-layer isolation, insulating layers for thin film amorphous silicon device structures and also for gate insulators in elemental and compound cemiconductor MOS field effect transistors (FET). Current trends in MOS technology are toward higher chip packing densities and larger substrates. To accomodate these trends MOS device dimensions must be reduced and high-temperature cycles in the fabrication process must be minimized. One of the most frequently used low temperature deposition processes is plasma enhanced chemical vapor deposition (PECVD), in which r.f. power provides the energy to promote faster low temperature reactions. However, films grown by conventional or 'Direct' PECVD generally contain high concentrations of bonded hydrogen, from 5 to 30 % as deduced from IR absorbtion measurements [1]. These impurities in the films can lead to chemical instabilities and also produce localized states in the band gap of the dielectrics which are electrically active as deep trapping and /or recombination centers [2]. Since the oxide layers under the gate electrode in MOSFETs are subjected to very high electric fields, the dielectric strength has an important bearing on device reliability. Electrical conduction in thin insulating films is complex in the sense that both electron and hole injection are important. High densities of bulk traps can modulate the conduction of these carriers, leading to poor device performance and instabilities. The currents in thin insulating films can generally be classified as being either bulk limited or electrode limited (3]. Because it has an extremely wide bandgap and high energy barriers at its electrodes, silicon oxides used in MOS device structure are likely to show electrode-limited conduction. In addition, if the density of bulk traps in the forbidden band is Mat. Res. Soc. Syrp. Proc. Vol. 105. 01968 Materials Research Society