595 THE GROWTH OF SILICON OXIDE FILMS BY REMOTE PLASMA ENHANCED CVD DV TSU and G LUCOVSKY Department of Physics, NC State Univ, Raleigh NC 27965-8202 ABSTRACT We have grown films of silicon oxide by remote Plasma Enhanced CVD (remote PECVD). By changing the fraction of 02 in a plasma excited 0/He mixture that is mixed with a fixed flow of SiHl 4 diluted with Ar, we can deposit films which are either Si-rich, stoichiometric or Si-deficient. These changes are accompanined by differences in the incorporation of bonded hydrogen which occurs in SiH groups in Si-rich films and SiOH groups in Si-deficient films. I INTRODUCTION There is interest in the low temperature deposition of silicon based dielectric films for microelectronics applications [1,2]. There have been studies of silicon oxide films deposited by direct plasma enhanced CVD (direct PECVD) using plasma excited mixtures of SiHl 4 and oxygen containing molecules, 02, N 2 0, C02' etc. [3]. These films are deposited on substrates immersed within the plasma and generally contain large amounts of bonded hydrogen, from 5 to 10 at.% in SiH, SiOH groups, etc. In addition; (a) the films show departures from Si0 2 stoichiometry; and (b) contain too many traps to be used as gate insulators in MIS structures. Similar considerations apply to direct PECVD nitride films, which usually contain even higher concentrations of bonded hydrogen, 20 to 30 at.% [3]. We [1,2] and other groups [4,5] have pursued an alternative approach to PECVD where; (a) only the oxygen containing reactant and rare gas diluents (He or Ar) are plasma excited; and (b) the substrate is outside of the plasma. We have developed this process where: (a) bonded hydrogen concentrations can be below the ir detection limit of 0.5 to 1 at.%, and (b) gate quality silicon oxide and nitride films can be deposited [1,2,6,7]. The major difference between direct PECVD and remote PECVD is in the way the Sill 4 reactant is used. In direct PECVD, the SiHl 4 is plasma excited leading to the generation of small molecules, SiHl2 and Sil3, which promote bonded hydrogen incorporation and departures from stoichiometry, whilst in remote PECVD it is consummed chemically by reactions involving the active oxygen species [8] yielding precursor molecules containing the Si-O-Si group. Another important difference, as already noted above, is in the placement of the substrate relative to the plasma. We have already discussed the deposition and characteriation of silicon nitride [6] and oxynitride films [7]; this paper discusses silicon oxide films. Mat. Res. Soc. Symp. Proc. Vol. 77. '1987 Materials Research Society