Optimized Deposition Parameters for Low Pressure Chemical Vapor Deposited Titanium Silicide

Abstract

A system and a process have been developed for the low pressure chemical vapor deposition (LPCVD) of titanium silicide. We report for the first time the optimization of LPCVD titanium silicide film properties against the deposition parameters, including the temperature, pressure, and flow rate ratios. Smooth, reproducible, low resistivity (15–20 μΩ‐cm) titanium silicide films have been deposited at a temperature of 730°C, a pressure of 67 mtorr, and a flow rate ratio of . The as‐deposited films did not require any post‐deposition annealing to achieve this low resistivity. All the as‐deposited films had a Si/Ti metal ratio of about 2 (determined by Rutherford backscattering spectroscopy). Within the Auger detection limit, no contamination was observed in the silicide films, and the films had uniform composition except for a transition region between the titanium silicide and the underlying polysilicon layers. During the experiments, it was observed that the flow rate ratio is the primary variable that affects the titanium silicide film properties. The rate of the silicon consumption during the silicide deposition has been determined and discussed in conjunction with the dependence of this rate on the flow rate; increasing the flow increases the polysilicon consumption rate.