Deposition kinetics of silicon dioxide from hexamethyldisilazane and oxygen by PECVD

Silicon oxide films were deposited on silicon wafers of 200 degrees C in a radio frequency reactor from gas mixtures of hexamethyldisilazane and oxyge n at various discharge powers and oxygen flow rates. Kinetics of the deposi tion of silicon dioxide was studied by using a simple surface chemistry mod el combined with the electron induced dissociation model developed in our p revious work. The validity of the combined model was examined by investigat ing the behavior of the incorporation rate of Si-O-Si bonds into the films in terms of the discharge power. According to the model, in the regime of t he negligible contribution of ion bombardment the incorporation rate psi, i s expressed as psi(infinity)/psi = 1 + chi(-1) P-rf(-1), with psi(infinity) = psi at the discharge power, P-rf = infinity.chi is a parameter independe nt of P-rf and designates the efficiency of dissociation of oxygen molecule s per inputted power under the experimental conditions of this work. The ex perimental results showed that the incorporation rate for the films deposit ed at oxygen flow rates of 10, 30 and 50 sccm and at a monomer flow rate of 3 g/h followed the prediction of the model very well. The values of chi we re estimated to be in the order of similar to 1.0 x 10(-2)W(-1) and decreas ed as the oxygen flow rate increased. The decrease in chi was explained by using the uniform discharge model for an electronegative discharge. (C) 199 9 Elsevier Science S.A. All rights reserved.