High performance 0.1 mu m gate-length p-type SiGe MODFET's and MOS-MODFET's

High performance p-type modulation-doped field-effect transistors (MODFET's ) and metal-oxide semiconductor MODFET (MOS-MODFET) with 0.1 mu m gate-leng th have been fabricated on a high hole mobility SiGe/Si heterojunction grow n by ultrahigh vacuum chemical vapor deposition. The MODFET del ices exhibi ted an extrinsic transconductance (g(m)) of 142 mS/mm, a unity current gain cut-off frequency (f(T)) Of 45 GHz and a maximum oscillation frequency (f( MAX)) Of 81 GHz, 5 nm-thick high quality jet-vapor-deposited (JVD) SiO2 was utilized as gate dielectric for the MOS-MODFET's. The devices exhibited a lower gate leakage current (1 nA/mu m at T-gs = 6 V) and a wider gate opera ting voltage swing in comparison to the MODFET's, However, due to the large r gate-to-channel distance and the existence of a parasitic surface channel , MOS-MODFET's demonstrated a smaller peak g(m) of 30 mS/mm, f(T) of 38 GHz , and f(MAX) of 64 GHz. The threshold voltage shifted from 0.45 V for MODFE T's to 1.33 V for MOS-MODFET's, A minimum noise figure (NFmin) of 1.29 dB a nd an associated power gain (G(a)) of 12.8 dB were measured at 2 GHz for MO DFET's, while the MOS-MODFET's exhibited a NFmin of 0.92 dB and a G(a) of 1 2 dB at 2 GHz, These de, rf, and high frequency noise characteristics make SiGe/Si MODFET's and MOS-MODFET's excellent candidates for wireless communi cations.