SiGe source/drain structure for the suppression of the short-channel effect of sub-0.1-μm p-channel MOSFETs

A bandgap engineering technique is proposed for the suppression of the short-channel effect (SCE) and its effectiveness is quantitatively calculated in the case of the SiGe source/drain structure with a device simulation. The drain-induced barrier lowering (DIBL) and the charge sharing are suppressed by the presence of the valence band discontinuity between the SiGe source/drain and Si channel. In order to obtain the full advantage of this structure, it is necessary to locate the SiGe layers both at the source/drain regions and the SiSe/Si interface at the pn junction or inside the channel region. The effectiveness increases with the increase of the valence band discontinuity (Ge concentration). As a result of the suppression of the SCE and the reduction of the minimum gate length, the drain current increases, and thus high-speed operation can be realized with this technique.