Effects on selective epitaxial growth of strained-SiGe p-MOSFETs on various (001) Si recess structures

Influences of source and drain recess structures on SiGe epitaxy growth, SiGe step height, facet formation, ID,sat and resistance performance are investigated. Growth rate of SiGe height increases with decreased recess width at a fixed depth of 62 nm. Under a fixed recess width of 96.3 nm, the deeper the recess, the higher the growth rate of SiGe height. An increase in the depth/width ratio of the recessed Si geometry may promote SiGe {001} growth. Upon the recess, SiGe step height is influenced by the initial SiGe orientation. A longer {001} facet of SiGe initial orientation causes a higher growth rate of SiGe step height. Higher IDsat and lower resistance can be achieved by increasing SiGe volume with wider recess width, deeper recess depth, and higher SiGe step height.