Comparison of ratio of gate length to gate-drain distance influences on source access resistance of AlGaN/AlN/GaN HFETs at different temperatures

In this work, two AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) with different ratios of gate length (LG) to gate-drain distance (LGD) were used to compare the effects of ratio of LG to LGD on the source access resistance (RGS) at 300 K, 350 K, and 400 K. The results showed that the ratio of LG to LGD had a significant effect on RGS at the above-mentioned each temperature, which can be attributed to the polarization Coulomb field (PCF) scattering. In addition, the effects of the ratio of LG to LGD on RGS in the two AlGaN/AlN/GaN HFETs prepared in this work were different at different temperatures. This indicated that elevated-temperature performance of AlGaN/AlN/GaN HFETs can be improved by optimizing the ratio of LG to LGD based on PCF scattering. [Display omitted] •The effects of the ratio of LG to LGD on RGS in AlGaN/AlN/GaN HFETs are investigated at different temperatures.•It is found that the ratio of LG to LGD has a significant effect on RGS at each testing temperature.•PCF scattering is responsible for the effects of the ratio of LG to LGD on RGS.•RGS can be modulated by optimizing the ratio of LG to LGD based on PCF scattering.