Dynamic RON Degradation in AlGaN/GaN MIS-HEMTs With Si3N4 or Si3N4/ZrO2Passivation Layer

The dynamic {R}-{ mathrm{scriptscriptstyle ON}} degradation in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) with different passivation layers (SiSi3N4 or Si3N4/ZrO2 stack) under off-, semi-on, and ON-state stress have been investigated in this work. Under the OFF-state stress of 40 V, a 20% reduction in the maximum drain current has been observed in devices passivated with Si{3}N{4}, along with a degraded {R}-{ mathrm{scriptscriptstyle ON}} that is 1.42 times higher than the initial {R}-{ mathrm{scriptscriptstyle ON}}. In contrast, devices passivated with Si3N4 or Si3N4/ZrO2 stack have only shown a 2% reduction, and the {R}-{ mathrm{scriptscriptstyle ON}} degradation is only 1.03 times higher than the initial {R}-{ mathrm{scriptscriptstyle ON}}. This can be attributed to the different interface states present in the two devices. According to the multifrequencyvphantom {-{int -{text {a}}}}~{C} -{V} curves, the Si3N4/GaN-cap interface trap density is in the range of 2times 10{{13}} -5.5times 10{{13}} from {E}-{C}-{0.47} to {E}-{C}-{0.37} eV, and ZrO2/GaN-cap interface trap density is in the range of 2.7times 10{{12}} -1.2times 10{{13}} from {E}-{C}-{0.47} to {E}-{C}-{0.31} eV. Under the semi-on state stress, the dynamic {R}-{ mathrm{scriptscriptstyle ON}} degradation exhibits a 'bell-shaped' behavior in the Si3N4 or Si3N4/ZrO2 stack passivated sample. Arrenhius plots indicate that the sample passivated by Si3N4 has an activation energy of 0.06 eV, while the sample passivated by Si3N4 or Si3N4/ZrO2 stack has an activation energy of 0.16 eV, which means a deeper trap distribution. The {R}-{ mathrm{scriptscriptstyle ON}} degradation under semi-on/ ON-state stress in Si3N4 or Si3N4/ZrO2 passivated devices can be attributed to the hot-electron-related injection mechanism. Device designers must consider the trade-off between the high breakdown voltage (BV) and the {R}-{ mathrm{scriptscriptstyle ON}} degradation in Si3N4 or Si3N4/ZrO2 passivated devices.