GexSi1-x/Si Heterostructures: Physics and Device Application

Breakthroughs in the strained layer growth of GexSi1-x on Si have at last provided the basis for a silicon based heterojunction technology. The combination of strain and artificial layer perioicity can yield properties beyond those found in the constituent semiconductors. The alterations include, strain dependent reductions in bandgap, variable bandedge alignment, piezoelectric effects suggesting non- random atomic ordering, and new optical transitions in ultrafine superlattices. These will be discussed along with the device results on silicon based optical detectors and modulation doped transistors.