New opportunities for SiGe and Ge channel p-FETs

A thin body (fully depleted) strained SGOI device structure (FDSGOI), and a strained SiGe channel layer on SOI, were fabricated using scaled high-@k gate dielectrics and metal gate technology. The uniaxial strain effect and corresponding drive current enhancement reported by Irisawa et al. [1] for narrow-width devices was investigated on these structures. Although the strained FDSGOI device structure exhibited reduced off-state leakage compared to thicker body devices, and long-channel drive current enhancement under uniaxial strain, the loss of drive current enhancement at short channel length led to uncompetitive I"O"N-I"O"F"F characteristics. The SiGe on SOI structure showed the highest long-channel drive current enhancement (nearly 3x) in the narrowest devices, and also showed a significant reduction in off-state current. This trend was maintained down to the shortest channel lengths studied here and resulted in I"O"N-I"O"F"F characteristics that were competitive with contemporary uniaxial strained Si channel devices.