THE KINK EFFECTS IN NANO-GaAs DEVICES DUE TO MULTI-VALLEY ELECTRON TRANSPORT

Abstract

The threshold source-drain voltage for the kink occurring in 130 nm GaAs devices is found to be linear dependent on the temperature in experiments. And the source-drain current after kink is also observed to be linearly dependent on the reciprocal of the source-drain voltage. A physical model of source-drain current including multi-valley transport for arbitrary doping and uniform doping GaAs has been proposed to explain such experimental phenomenon. Multi-valley electron transport origins from electrons getting the energy higher than the energy difference between the valleys from the channel electric field due to channel length shorter than the free-length for nano- GaAs devices. High energy electrons due to ballistic transport leads to a redistribution channel electron in different valleys and high energy electrons have a larger probability to occupy the states in upper valley because the density of states of the upper valley is about 70 times larger than that of the lower valley, leads to the carrier density in L valley being comparable with that in Γ valley in the channel, lastly kinks occurs.