Two-dimensional clusters in SiGe/Si heterostructures and their effect on field effect transistor transport characteristics

Heterostructures of Si0.80Ge0.20/Si (100) were grown by pulsed laser deposition with alternating 10 nm SiGe and Si layers for a total of 10 periods. The presence of alloy clustering at SiGe/Si interfaces was investigated by parallel transport in transistor structures. Monte Carlo methods were used to calculate the transport effects on the lateral transport in a field effect transistor configuration. High electron mobility transistors are fabricated with two conducting 2D channels consisting of Si/SiGe/Si grown on high resistivity (100) silicon to measure the effect of clustering. Using 0.5 μm gates, a transconductance of 125 mS/mm is obtained in transistors without alloy clustering which decreased to less than 80 mS/m when alloy clustering is present.