HIGH-ELECTRON-MOBILITY IN STRAINED SI CHANNEL OF SI1-XGEX SI/SI1-XGEXHETEROSTRUCTURE WITH ABRUPT INTERFACE/

Si1-xGex/Si/Si1-xGex heterostructures with high electron mobility were grown by molecular beam epitaxy (MBE) combined with solid-phase epita xy (SPE). The SPE growth completely suppressed Ge segregation in the S i1-xGex layer on top of the Si channel layer. High-resolution cross-se ctional transmission electron microscopy observation revealed that the heterointerfaces formed by the SPE growth technique were very flat co mpared with those for the MBE-grown samples. The electron mobility for an SPE-grown sample with a graded buffer layer was nearly one order o f magnitude higher than without such a layer. A high electron mobility of 8.0 x 10(5) cm(2) V-1 s(-1) was obtained at 15 K for the sample wi th a graded buffer layer (x = 0.2).