The thermal oxidation of Si was used to characterize the interaction of Si interstitials with a Si1-xGex layer, and with B in Si1-xGex. The diffusion of B in a Si marker layer under a Si1-xGex layer was monitored as excess Si interstitials were injected into the bulk via oxidation of the Si capping layer. It was found that the Si1-xGex layer did not affect the oxidation-enhanced diffusion of B in the Si marker layer. Therefore, Si1-xGex (with x less than 0.30) did not appear to be a strong sink for Si interstitials. In addition, the enhancement of the measured B diffusivity in Si1-xGex (table 4), which arose from Si thermal oxidation, was similar to that in Si. It was concluded that, as in the case of Si, the mechanism of B diffusion in Si1-xGex (for x-values of less than 0.18) involved mainly interstitials.

P.Kuo, J.L.Hoyt, J.F.Gibbons, J.E.Turner, D.Lefforge: Applied Physics Letters, 1995, 67[5], 706-8

Table 4

Intrinsic Diffusivity of B in Si1-xGex