Dynamic Performance Analysis of Logic Gates Based on p-GaN/AlGaN/GaN HEMTs at High Temperature

The high-temperature operation of the AlGaN/GaN high electron mobility transistors (HEMTs) and direct-coupled FET logic (DCFL) inverters, NOR gates, and NAND gates are demonstrated. The <inline-formula> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula>-GaN-gate HEMTs which are used as drivers in DCFL circuits exhibit proper E-mode operation with a relatively stable threshold voltage <inline-formula> <tex-math notation="LaTeX">${V}_{\text {TH}}$ </tex-math></inline-formula> (drift −0.31 V) and high electron mobility <inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> of 587 cm2/<inline-formula> <tex-math notation="LaTeX">$\text{V}\cdot \text{S}$ </tex-math></inline-formula> at 300 °C. The fabricated logic gates have a small switching time at room temperature (RT). As the temperature increases to 300 °C, these logic gates exhibit a slight increase in switching time, wherein the fall time and rise time of the inverter from room temperature to 300 °C increases from 16 ns to 129 ns and 128 ns to <inline-formula> <tex-math notation="LaTeX">$0.864~\mu \text{s}$ </tex-math></inline-formula>, respectively. The logic gates herein exhibit accurate and stable operation at 300 °C. Furthermore, the reason for the switching time increase at high temperature is revealed from the perspective of devices.