Fabrication and current-voltage characterization of a ferroelectric lead zirconate titanate/AlGaN∕GaN field effect transistor

We demonstrated ferroelectric field effect transistors (FFETs) with hysteretic I-V characteristics in a modulation-doped field effect transistors (MODFET) AlGaN∕GaN platform with ferroelectric Pb(Zr,Ti)O3 between a GaN channel and a gate metal. The pinch-off voltage was about 6–7V comparable to that of conventional Schottky gate MODFET. Counterclockwise hysteresis appeared in the transfer characteristics with a drain current shift of ∼5mA for zero gate-to-source voltage. This direction is opposite and much more pronounced than the defect induced clockwise hysteresis in conventional devices, which suggests that the key factor contributing to the counterclockwise hysteresis of the FFET is the ferroelectric switching effect of the lead zirconate titanate gate.