Mobility, transit time and transconductance in submicrometre-gate-length m.e.s.f.e.t.s

Two-dimensional simulations of submicrometre-gate-length m.e.s.f.e.t.s of Si, GaAs and InP show that device transit time and transconductance depend more on high-field diffusion constant and the shape of the velocity/field characteristic than on low-field mobility. Reasonable InP devices have shorter transit times and higher transconductances than GaAs devices, and for certain device parameters these figures of merit can be almost the same for Si and GaAs devices.