p-Type SiGe transistors with low gate leakage using SiN gate dielectric

Using high-quality jet-vapor-deposited (JVD) SiN as gate dielectric, p-type SiGe transistors are fabricated on SiGe heterostructures grown by ultra-high-vacuum chemical vapor deposition (UHVCVD). For an 0.25-μm gate-length device, the gate leakage current is as small as 2.4 nA/mm at V/sub ds/=-1.0 V and V/sub gn/=0.4 V. A maximum extrinsic transconductance of 167 mS/mm is measured. A unity current gain cutoff frequency of 27 GHz and a maximum oscillation frequency of 35 GHz are obtained.