High radiation tolerance of InAs∕AlSb high-electron-mobility transistors

In As ∕ Al Sb -based high-electron-mobility transistors (HEMTs) were irradiated with 2MeV protons. Radiation damage caused the source-drain current Ids to decrease nearly linearly with fluence Φ at a rate of Δ[Ids(Φ)∕Ids(0)]∕ΔΦ≈7×10−16cm2. Radiation-induced decreases in Ids have been observed for other HEMT material systems, and have been attributed to high-efficiency defect-induced scattering of carriers out of the two-dimensional electron gas. However, in the InAs∕AlSb system the rate of decrease of Ids is about 140 times less than that for typical GaAs∕AlGaAs HEMTs. An explanation is presented in which the high radiation tolerance of InAs∕AlSb HEMTs is related to carrier reinjection and the unusually large energy offset between the AlSb barriers and the InAs quantum well.