Investigation of point-defect generation in silicon during oxidation of a deposited WSi2 layer

Abstract

In recent letters it was reported from separate studies that silicidation of the refractory metals TaSi2 or TiSi2 on a silicon surface gives rise to injection of vacancy point defects into the underlying substrates. In both studies it was proposed that a vacancy influx may be induced by a silicon efflux during silicidation. In this work we show that during oxidation of WSi2 on silicon, which also causes an efflux of silicon atoms from the underlying substrate, no vacancy excess is observed based on monitoring diffusion of P and B buried marker layers. We also propose a possible explanation that reconciles the apparently discrepant findings that B diffusion is always retarded during vacancy supersaturations resulting from thermal nitridation reactions, while vacancy supersaturations observed during silicidation of TaSi2 result in enhanced diffusion of B.