Excellent electrostatic control and gate reliability for breakdown enhanced AlGaN/GaN HEMTs with extreme permittivity BaTiO3

Abstract

In this Letter, we investigated the electrostatic control capability and gate reliability of the BaTiO3 integrated AlGaN/GaN HEMTs. The fabricated HEMT exhibits a high peak maximum transconductance of 141 mS/mm, a large ON/OFF current ratio of 4.1 × 109, and a small subthreshold swing of 70.6 mV/dec, attributed to the gate leakage suppression and prominent gate coupling. These parameters demonstrate that the HEMT device with extreme permittivity BaTiO3 dielectric has the excellent electrostatic control capability. A high breakdown voltage of 1348 V was also achieved thanks to the screening of the negative gate image charges and the resulting improvement of electric field distribution by using double-layer BaTiO3 with the wrapped gate structure. Furthermore, gate bias step-stress and pulse I–V measurements show that the device exhibits a small VTH shift of 0.06 V at 2 V bias stress and a slight current collapse of ∼2.7% accompanied with a 6.0% RON increment at a quiescent drain bias VDSQ = 30 V, which benefits from the high quality of the dielectrics/AlGaN interface with Dit of 8.87 × 1012 eV−1/cm2. These findings elucidate the immense potential of extreme permittivity dielectrics engineering in achieving high-performance AlGaN/GaN power electronic devices.