By providing an asymmetric design of a halo region and extension regions of a field effect transistor, the transistor performance may significantly be enhanced for a given basic transistor architecture. In particular, a large overlap area may be created at the source side with a steep concentration gradient...http://www.google.de/patents/US7208397?utm_source=gb-gplus-sharePatent US7208397 - Transistor having an asymmetric source/drain and halo implantation region and a method of forming the same
