MOSFETs with ultrashallow junction and minimum drain area formed by using solid-phase diffusion from SiGe

An advanced CMOS structure, in which a raised source/drain and contact windows formed over the field oxide, was fabricated. Ultrashallow junction formation using solid-phase diffusion from doped SiGe layers was used to fabricate MOSFETs. These MOSFETs demonstrated excellent short-channel characteristics and 70%-80%-reduced parasitic drain-junction capacitance. They have ultrashallow junctions with a depth of 25 nm and a low source/drain extension (SDE) resistance: 350 Ω/sq (NMOSFETs) and 390 Ω/sq (PMOSFETs). The isotropic diffused SDE structure was formed by using solid-phase diffusion, which could effectively form a shallow junction and a suitable overlap between gate and SDE. This structure results in good short-channel characteristics and high current drivability