of contact formation is completed as in fig1 during the reaction of the metal 80 with the underlying silicon layer 170 over silicon germanium alloy 162 u2032 and with the underlying silicon layer 270 over the n doped si c alloy 262 u2032 the metal 80 is reacted with all the silicon material that was deposited during the selective silicon deposition the resulting structure for the pfet 321 and the resulting structure for the nfet 421 are shown in fig1 each one of the source and drain regions for a pfet contains a stack of an unalloyed metal silicide 186 and an electrically doped epitaxial silicon germanium alloy layer 162 u2032 each one of the source and drain regions for an nfet contains a stack of an unalloyed metal silicide 286 and an n doped si c alloy 262 u2032 allowing the reaction of the metal to consume a portion of the underlying doped silicon germanium alloy 162 u2032 or a portion of the underlying n doped si c alloy 262 u2032 is also contemplated herein the third through the twelfth embodiments of the present invention use the elements of the first and second embodiments of the present invention with some alteration description of these embodiments is done first by comparing the differences across the various embodiments of the present invention and then specific features and ramifications of each embodiment are described the twelve embodiments are classified into two groups of embodiments a first group of embodiments include the first through sixth.