MOSFETs on self-assembled SiGe dots with strain-enhanced mobility

Silicon-germanium dots grown in the Stranski-Krastanow mode are investigated as sources of strain for electron mobility enhancement in the silicon capping layer. N-channel MOSFETs with the channel in the Si cap-layer over the SiGe dot (DotFETs) are fabricated in a custom-made process and have an average increase in drain current of up to 22.5% compared to the reference devices. The sources of device variations related to the dimensions of the main gate-segment are identified and their influence on device performance evaluated, confirming the mobility enhancement.