Properties of titanium silicide films deposited by plasma-enhanced chemical vapor deposition

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Abstract
Titanium silicide is a desirable interconnect material for future very large scale integrated circuit (VLSI) devices because of its low resistivity (15 μΩ cm) and because of its low sinter temperature (600 °C) compared to other refractory metal silicides. Chemical vapor deposited (CVD) films have much better purity and step coverage than the conventional physical vapor deposited (PVD) films. A study has been made of titanium silicide deposited by plasma-enhanced CVD (PECVD). Rutherford backscattering has been used to analyze the dependence of the as-deposited film composition on the process parameters. The changes in the composition and the resistivity of the films during both furnace and rapid thermal anneals have been studied. It has been shown that it is possible to grow a SiO2 layer on top of the silicide film when a proper clean of the substrate surface is done before the deposition. Stress levels after anneal are about 1×1010 dyn/cm2. Anisotropic etch of the film is possible even when deposited on a polysilicon substrate.