High-performance AlGaN/GaN HEMTs with Hf0.5Zr0.5O2-based ferroelectric gate by pulsed laser deposition

This Letter demonstrates AlGaN/GaN high-electron-mobility transistors (HEMTs) with Hf0.5Zr0.5O2 (HZO) ferroelectric gate dielectric using pulsed laser deposition (PLD). An ultrathin Al2O3 interlayer grown by atomic layer deposition is used to avoid destroying the AlGaN surface and decreasing the electron density of a two-dimensional electron gas channel before PLD. The high-quality HZO on AlGaN/GaN heterostructure contributes to the good insulating and ferroelectric properties of the HZO film, yielding a superior ON/OFF current ratio of 4 × 1011 and a low sub-threshold slope (SS) of 53.2 mV/dec. Moreover, the electrical characteristics of the device are systematically investigated before and after gate poling. In combination with the analysis of schematic band diagrams, we found that ferroelectric polarization can effectively regulate the capture and release processes of channel electrons by Al2O3/AlGaN interface defects. These results show that HZO-based ferroelectric HEMTs have great potential for high frequency, low power consumption, and multi-functional devices.