Enhancement of ballistic transport in an AlGaAs/InGaAs high electron mobility transistor at low temperatures

The authors investigated the current-voltage characteristics of a 100 nm AlGaAs/InGaAs pseudomorphic high electron mobility transistor as a function of temperature. The drain current in the linear region showed a dramatic increase when the temperature was lowered below a critical value (T_B) and the drain voltage is increased. A quantitative analysis based on self-consistent Schrödinger-Poisson and simple electrostatic band potential profile calculations was performed to model the transmission coefficient. The modeled results are consistent with the measured data, confirming that the main transport mechanism switches from a classical drift-diffusion transport into a quasiballistic transport when decreasing temperature below T_B and increasing drain voltage.