Contact Resistance Reduction Technology Using Aluminum Implant and Segregation for Strained p-FinFETs With Silicon–Germanium Source/Drain

We have demonstrated the introduction of an additional aluminum (Al) implant step in the fabrication of strained p-FinFETs with silicon-germanium (SiGe) source/drain (S/D). Al is implanted. into the p⁺-SiGe S/D region at energy of 10 keV and a dose of 2 × 10¹⁴ atoms/cm², followed by its segregation at the NiSiGe/p⁺-SiGe S/D interface during germanosilicidation. The presence of Al at this interface leads to lowering of the effective Schottky barrier height for hole conduction, which, in essence, lowers the S/D contact resistance R_C · R_C is a dominant component of the FinFET parasitic series resistance R_SD, which is lowered by approximately 25% using this technology, correspondingly leading to a substantial increase in the saturation drive current. The novel Al-segregated NiSiGe/p⁺-SiGe S/D contact junction in p-FinFETs does not degrade short-channel effects or the NiSiGe film morphology.