The injection of Si self-interstitials, during the oxidation of a Si-cap layer in Si/SiGe/Si heterostructures, was used to characterize the atomic mechanism of Sb diffusion in strained SiGe films. A marked retardation of Sb diffusion was observed in Si0.9Ge0.1 and Si0.8Ge0.2 spacers which were subjected to interstitial injection at 900 and 825C, respectively (table 29). As a control, the retardation of Sb diffusion during oxidation was monitored simultaneously in Sb-doped Si buffer layers of Si/SiGe/Si heterostructures. The measurements indicated that, in strained SiGe (as in Si), the mechanism of Sb diffusion involved mainly vacancies; with an interstitialcy fraction close to that in Si. That is, less than in 0.02 in Si0.9Ge0.1.

Effect of Injection of Si Self-Interstitials on Sb Diffusion in Si/Si1-xGex/Si Heterostructures A.J.Kuznetsov, J.Grahn, J.Cardenas, B.G.Svensson, J.L.Hansen, A.N.Larsen: Physical Review B, 1998, 58[20], R13355-8

Table 29

Diffusivity of Sb in Si1-xGex