The study of parallel strain distribution in channel of PMOSFET with silicon-germanium source and drain regions

The finite-element model of strained silicon PMOSFET was established based on the structure of small uniaxial strained silicon device. Using thermal strain method to simulate the parallel strain distribution of the channel through ANSYS simulation platform. The results present that: (1)the compressive strain on the channel surface is quite uniform along the direction parallel to the channel, the compressive strain in the center of channel decreases with the increasing distance from the channel surface, which transforms into tensile strain when the distance reaches or beyonds the etching depth of silicon-germanium source and drain. (2)the strain in the channel will correspondingly increase with the decreasing channel length or increasing etching depth of silicon-germanium source and drain or increasing germanium fraction of source and drain. The conclusion provides a design basis to improve the device performance by controlling the strain, in addition, the conclusion is in line with the relevant literature.