Strained silicon-on-insulator - Fabrication and characterization

SSOI substrates were successfully fabricated using He+ ion implantation and annealing to relax thin (< 500nm) SiGe buffer layers, bonding and layer transfer processes to realize strained-Si layers onto oxide layers. The reduced thickness of the SiGe buffer possess numerous advantages such as reduced process costs for epitaxy and for reclaim of the handle wafer if the layer splitting is initiated in the SiGe/Si interface. The electron mobilities in the fabricated SSOI layers were measured using transistors with different gate lengths. An electron mobility of ~530 cm2 /Vs was extracted, being much higher than in non-strained SOI substrates. Furthermore, an 80% drive current (IDSAT) improvement has been measured for long channel devices.