Demonstration of N-Polar All-AlGaN High Electron Mobility Transistors With 375 mA/mm Drive Current

Devices made from ultrawide bandgap (UWBG) materials are being widely investigated for high-power and radio frequency (RF) electronics. High electron mobility transistor (HEMT) is one of the most effective designs to implement heterostructures in III-Nitrides and III-Oxides that leverage a 2D-channel with high conductivity and large breakdown electric field. Nitrogen (N)-polarity in GaN channel HEMTs have shown remarkable performance advantage in both power and RF applications compared to its metal-polar counterpart. Here, UWBG N-polar AlGaN channel HEMT can bring further performance benefits due to an increase in the channel's breakdown electric field. In this work, we report the first experimental demonstration of N-polar all-AlGaN HEMT devices with two different Al compositions (20% and 30%) in the channel. The HEMT with 3 mu m long-channel (20% Al) showed a drive current of 375 mA/mm (at 0 V gate voltage). These devices also show low on-state leakage current of similar to 0.5 nA/mm, and large on/off ratio of similar to 2 x 10(8). Furthermore, >400 V breakdown voltage was achieved without any field plate structures.

Automated summary

Devices made from ultrawide bandgap materials are being widely investigated for high-power and RF electronics. Nitrogen-polar GaN channel HEMTs exhibit better performance compared to their metal-polar counterparts. In this work, the first experimental demonstration of N-polar all-AlGaN HEMT devices with different Al compositions (20% and 30%) in the channel is reported. These devices showed high drive current, low leakage current, large on/off ratio, and high breakdown voltage without field plate structures.