Lattice-Mismatched $\hbox {In}_{0.4}\hbox {Ga}_{0.6} \hbox {As}$ Source/Drain Stressors With In Situ Doping for Strained

We report the first demonstration of a strained In_0.53 Ga_0.47As channel n-MOSFET featuring in situ doped In_0.4Ga_0.6As source/drain (S/D) regions. The in situ silicondoped In_0.4Ga_0.6As S/D was formed by a recess etch and a selective epitaxy of In_0.4Ga_0.6As in the S/D by metal-organic chemical vapor deposition. A lattice mismatch of ~ 0.9% between In_0.53Ga_0.47As and In_0.4 Ga_0.6As S/D gives rise to lateral tensile strain and vertical compressive strain in the In_0.53Ga_0.47As channel region. In addition, the in situ Si-doping process increases the carrier concentration in the S/D regions for series-resistance reduction. Significant drive-current improvement over the control n-MOSFET with Si-implanted In_0.53Ga_0.47As S/D regions was achieved. This is attributed to both the strain-induced band-structure modification in the channel that reduces the effective electron mass along the transport direction and the reduction in the S/D series resistance.