Analyis of hole mobility and strain in a Si/Si0.5Ge0.5/Si metal oxide semiconductor field effect transistor

The hole mobility has been measured in a metal-oxide semiconductor field-effect transistor featuring a 6 nm Si0.5Ge0.5 conduction channel. Physical characterization and analysis of the electrical properties confirm that the channel is fully strained. At a total sheet carrier concentration, PS, of 10(12) cm(-2), the 300 K mobility of 220 cm(2) V-1 s(-1) is double that of a Si control device (and at 4 K has a peak value of 1800 cm(-2) V-1 s(-1)). This improvement is largely maintained up to p(s) similar to 10(13) cm(-2) , despite the onset of conduction in a parallel Si channel at the oxide interface. Comparing the measurements with calculations suggests that the mobility is affected more strongly by interface toughness than by alloy scattering.