Sidewall Dislocations in Embedded SiGe Source/Drain Areas of MOSFETs and their Impact on the Device Performance

摘要

Performance and structural quality of stress-engineered MOSFET devices with embedded strained SiGe Source/Drain elements have been studied by means of transmission electron microscopy, computer modeling and electrical characterization. Characteristic crystal defects were often observed at the sidewalls of SiGe elements. The presence of the defects correlated with the decrease in MOSFET drive currents. Both measurements of silicon lattice parameters in the device structures using nano-beam diffraction and stress modeling indicated that stresses in channels of the MOSFETs with SiGe defects were not significantly lower. It is concluded that the sidewall SiGe dislocations relate to the device performance degradation through the carrier scattering mechanisms.