Silicide as diffusion source for dopant segregation in 70-nm MOSFETs with PtSi Schottky-barrier source/drain on ultrathin-body SOI

In this paper, dopant segregation (DS) method is adopted to enhance device performance of PtSi-based Schottky-barrier source/drain MOSFETs (SB-MOSFETs) fabricated on ultrathin silicon-on-insulator. The DS formation is realized by means of Silicide As Diffusion Source. Without DS treatment, the devices are typically p-type, but with a rather large electron branch at positive gate bias. Dopant segregation with As is found to turn the devices to well-performing n-MOSFETs, and DS with B to greatly enhance the hole conduction in the p-MOSFETs. A large threshold voltage (Vt) shift is however observed in the p-MOSFET due to B lateral spread caused during the drive-in process for the DS formation. By reducing the drive-in temperature, this problem is partially addressed with a smaller Vt shift and a much better control of short channel effect.