Enhancement mode Ga2O3 wrap gate fin field effect transistors on native (100) b Ga2O3 substrate with high breakdown voltage
Sn doped gallium oxide (Ga2O3) wrap gate fin array field effect transistors (finFETs) were formed by top down BCl3 plasma etching on a native semi insulating Mg doped (100) b Ga2O3 substrate. The fin channels have a triangular cross section and are approximately 300 nm wide and 200 nm tall. FinFETs, with 20 nm Al2O3 gate dielectric and ~2 mm wrap gate, demonstrate normally off operation with a threshold voltage between 0 and +1 V during high voltage operation. The ION/IOFF ratio is greater than 105 and is mainly limited by high on resistance that can be significantly improved. At VG 0, a finFET with 21 mm gate drain spacing achieved a three terminal breakdown voltage exceeding 600 V without a field plate.