A self-aligned process used to fabricate p-type SiGe metal-oxide-semiconductor modulation-doped field effect transistors (MOS-MODFET) is described. Self- and nonself-aligned p-type Si0.2Ge0.8/Si0.7Ge0.3 MOS-MODFETs with gate-lengths from 1 mum down to 100 nm were fabricated. The de and microwave characteristics of these devices are presented. In comparison with nonself-aligned devices, self-aligned devices exhibited higher extrinsic transconductances, lower threshold voltages, higher unity current gain cutoff frequencies f(T), and maximum oscillation frequencies f(MAX). Self-aligned MOS-MODFETs with a gate length of 100 nm. exhibited an extrinsic transconductance of 320 mS/mm, an f(T) of 64 GHz, and an f(MAX) of 77 GHz. To our knowledge, these are the highest data ever reported for any MOS-type p-FETs with a SiGe channel. All these excellent performances were measured at very low drain and Sate biases.