Fabrication and Evaluation of N-Channel GaN Metal–Oxide–Semiconductor Field-Effect Transistors Based on Regrown and Implantation Methods

We have demonstrated the enhancement-mode n-channel gallium nitride (GaN) metal-oxide field-effect transistors (MOSFETs) on homoepitaxial GaN substrates using the selective area regrowth and ion implantation techniques. Both types of MOSFETs perform normally off operations. The GaN-MOSFETs fabricated using the regrowth method perform superior characteristics over the other relative devices fabricated using the ion implantation technique. The electron mobility of 100 cm(2)/V·s, subthreshold of 500 mV/dec, and transconductance of 14 μs/mm are measured in GaN-MOSFETs based on the implantation technique. Meanwhile, the GaN-MOSFETs fabricated using the regrowth method perform the electron mobility, transconductance, and subthreshold of 120 cm(2)/V s, 18 μs/mm, and 300 mV/dec, respectively. Additionally, the MOSFETs with the regrown p-GaN gate body show the I(on)/I(off) ratio of approximately 4 × 10(7)(,) which is, to our knowledge, among the best results of GaN-MOSFETs to date. This research contributes a valuable information for the design and fabrication of power switching devices based on GaN.