Effect of injection of Si self-interstitials on Sb diffusion in Si/Si1-xGex/Si heterostructures

Injection of Si self-interstitials, during oxidation of a Si-cap layer in Si/Si1-xGex /Si heterostructures, is used to characterize the atomic mechanism of Sb diffusion in strained Si1-xGex films. Strong retardation of Sb diffusion is observed in Si0.9Ge0.1 and Si0.8Ge0.2 spacers subjected to interstitial injection at 900 and 825 degrees C, respectively. As a reference, the retardation of Sb diffusion (during oxidation) was monitored simultaneously in Sb-doped silicon buffer layers of Si/Si1-xGex/Si heterostructures. Our measurements indicate that in strained Si1-xGex, as in Si, the mechanism for Sb diffusion involves primarily vacancies with the interstitialcy fraction close to that in silicon (e.g., less than or equal to 0.02 in Si0.9Ge0.1). [S0163-1829(98)51544-5].