p-Type Ion Implantation in Tensile Si/Compressive Si0.5Ge0.5/Tensile Strained Si Heterostructures

We present a systematic study on the formation of p-type doped strained Si / strained SiGe heterostructures by B+, BF2+ and (Si++B+) ion implantation and annealing at moderate temperatures. The aim of this paper is to address the challenge of conserving the elastic strain during dopant activation. The most important result is that efficient doping combined with the conservation of strain and a good crystalline quality can only be obtained for BF2+ implants with 1x10(15) ions/cm(2) and anneals at 650 degrees C. With these parameters, single crystalline layers with negligible strain relaxation and a sheet resistance of 886 Omega/sq were achieved. The implantation of B+ requires higher doses to reach low sheet resistances resulting in low layer quality and higher strain relaxation. Si+ pre-implantation yields the lowest sheet resistances, but on the expense of strain (relaxation values over 60%). Finally, the optimized ion implantation / anneal parameters were applied for strained SiGe quantum-well MOSFETs with GdScO3 high-kappa gate dielectric. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.060201jes]