A novel enhance-mode AlGaN/GaN HEMT with split floating gates

摘要

A novel enhance-mode (normally-off) AlGaN/GaN HEMT structure is proposed and demonstrated. Concretely, a few nanometers of tunnel dielectric as well as several split floating gates (FGs) are inserted beyond the conventional MIS structure of the normally-on counterpart. The FGs are applied to storage negative charges by means of tunneling effect, thereby converting the HEMT to an enhancement mode. The simulation results revealed that the Vth is able to be increased by adjusting the charge densities of FGs. More interestingly, the split FGs could observably reduce the probability of leakage comparing with the single large area FG structure, thus improving the Vth stability. Moreover, it should also be noteworthy mentioning that under the same gate length, the devices lifetime will also be impacted by the number and length of FGs.