Strain distribution in a transistor using self-assembled SiGe islands in source and drain regions

We propose to improve a p-channel metal-oxide-semiconductor field-effect transistor using laterally closely spaced double self-assembled SiGe∕Si islands as drain and source to create a high hole mobility channel. The strain distribution in and around the channel is calculated for two realistic island geometries with various distances between the islands. A compressive strain of more than 1% in the channel can be achieved for SiGe islands and small distance between these two islands. We demonstrate that the proposed double SiGe∕Si island structure can be realized by epitaxial growth on patterned substrates designed for static random access memory cell.