TCAD ready density gradient calculation of channel charge for Si/strained Si/sub 1-x/Ge/sub x/ dual channel pMOSFETs on [001] relaxed Si/sub 1-y/Ge/sub y/

The dual channel MOSFET with strained Si/Si/sub 1-x/Ge/sub x/ layers on relaxed Si/sub 1-y/Ge/sub y/ is a promising structure for the improvement of CMOS performance because of its enhanced carrier mobilities (Hargrove, 1994). In order to obtain the correct threshold voltage and gate capacitance of these devices, it is essential to accurately model the channel charge distribution. In our study a dual channel MOSFET with an n-type substrate doping of 5 /spl middot/ 10/sup 17//cm/sup 3/ and a metal gate is investigated. The confinement of the holes to the strained SiGe region depends on the gate bias. For the first time accurate CV-characteristics for strained Si/SiGe dual channel pMOSFETs are calculated based on the density gradient method. These results make the direct application of commercially available TCAD tools feasible for the calculation of CV characteristics of such complicated structures.