Numerical study for enhancement-mode AlN/GaN/AlN N-polar MISFET with self-aligned source/drain regions

In this work, for the first time, the electrical characteristic of the enhancement-mode (E-mode) N-polar GaN metal-insulator-semiconductor field effect transistor with self-aligned source/drain regions is investigated by SILVACO TCAD software. Macroscopic polarization effect of III-V nitrides are included and are used to realize the Emode operation. Numerical study results show that E-mode N-polar GaN transistor can keep E-mode operation at the gate length of 0.62 μm, and the simulation result is in accordance with the experimental report result. As the gate length decreases, the short channel effect becomes severe and is able to change this E-mode device to depletion mode operation. The introduction of the vertical scaling technique is beneficial to suppress short channel effect to maintain the E-mode operation even if the gate length scales to below 100nm gate length. This detailed study in N-polar GaNbased transistors establishes technological base for further development of field effect devices based on N-polar IIInitrides. . Keywords-GaN; short channel effect; III-nitrides; MISFET; enhancement-mode