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

The dynamic <tex-math notation="LaTeX">RON </tex-math> 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 <tex-math notation="LaTeX">RON </tex-math> that is 1.42 times higher than the initial <tex-math notation="LaTeX">RON </tex-math> . In contrast, devices passivated with Si3N4 or Si3N4/ZrO2 stack have only shown a 2% reduction, and the <tex-math notation="LaTeX">RON </tex-math> degradation is only 1.03 times higher than the initial <tex-math notation="LaTeX">RON </tex-math> . This can be attributed to the different interface states present in the two devices. According to the multifrequency <tex-math notation="LaTeX">_∫ ₐ~C </tex-math> – <tex-math notation="LaTeX">V </tex-math> curves, the Si3N4/GaN-cap interface trap density is in the range of <tex-math notation="LaTeX">2× 10^13 </tex-math> – <tex-math notation="LaTeX">5.5× 10^13 </tex-math> from <tex-math notation="LaTeX">EC-0.47 </tex-math> to <tex-math notation="LaTeX">EC-0.37 </tex-math> eV, and ZrO2/GaN-cap interface trap density is in the range of <tex-math notation="LaTeX">2.7× 10^12 </tex-math> – <tex-math notation="LaTeX">1.2× 10^13 </tex-math> from <tex-math notation="LaTeX">EC-0.47 </tex-math> to <tex-math notation="LaTeX">EC-0.31 </tex-math> eV. Under the semi-on state stress, the dynamic <tex-math notation="LaTeX">RON </tex-math> 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 <tex-math notation="LaTeX">RON </tex-math> 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 <tex-math notation="LaTeX">RON </tex-math> degradation in Si3N4 or Si3N4/ZrO2 passivated devices.