Pt-AlGaN/GaN HEMT-sensor layout optimization for enhancement of hydrogen detection

This paper reports on the layout optimization of Pt-AlGaN/GaN HEMT-sensors for enhancing hydrogen sensor performance. Sensors with gate width and length ratios W-g/L-g from 0.25 to 10 were designed, fabricated and tested for the detection of hydrogen gas at 200 degrees C. Sensitivity, sensing current variation and transient response are directly related to the sensor gate electrode W-g/L-g ratio. The obtained results demonstrated a 217 % increase in sensitivity and 4630 % increase in sensing current variation at 500 ppm H-2 for a W-g/L-g from 0.25 to 10. In addition, the detection limit was lowered to 5 ppm. Transient characteristics demonstrated faster sensor response to H-2, but slower recovery rates with increasing ratio.