Reliability Comparison of Conventional & Two Finger AlGaN/GaN HEMT

Present work explore the reliability of single and two finger AlGaN/GaN HEMT using ATLAS TCAD software. Conventional AlGaN/GaN architecture has been first calibrated with the experimental results with reverse gate bias voltage induced stress results. The architecture has been further modified to explore the performance change (due to negative bias induced stress) in two finger AlGaN/GaN HEMT having two configurations: 1) Common Drain and 2) Common Source. The negative shift in drain current due to reverse gate voltage induced stress in two finger geometry is 2.3V, which is significantly higher than that of the conventional HEMT i.e. 1.75V. Significantly higher current has been achieved from two finger AlGaN/GaN HEMT as compared to conventional HEMT. However, approximately same drain current has been observed from two geometry of common drain and common source configuration of AlGaN/GaN HEMT. From the results it was observed that although the drain current is similar in two configurations of two finger geometry but significant variation in terms of parasitic capacitances has been seen. Lattice temperature and electric field for conventional HEMT and its two-finger geometry has also been explore using Electrothermal simulation. The deterioration in device characteristics due to self heating effect is also higher in two finger geometry as compared to conventional HEMT. Effect of substrate material on the device performance has also been explored.