Experimental study of β -Ga2O3 MOSFET with p -NiO source field plate for high-performance

In this work, we demonstrate a lateral Ga2O3 metal oxide semiconductor field effect transistor (MOSFET) with the p-NiO source field plate (PSFP). The PSFP consists of a p-NiO layer above the n-drift, which is shorted to the source electrode and isolated from Ga2O3 by an Al2O3 layer. In the OFF-state, the p-NiO not only modulates the electric field distribution to enhance breakdown voltage (BV) but also assists depleting the n-drift and allows an elevated doping concentration to reduce specific on-resistance (Ron,sp). In the ON-state, the Al2O3 dielectric layer suppresses the NiO-induced n-drift depletion, inhibiting Ron,sp degradation. Through the use of multiple-energy silicon ion implantations into the Ohmic contact regions and subsequent high-temperature annealing, an ultralow Ohmic contact resistance of 0.35 Ω mm is achieved. Compared with conventional MOSFET (Con. MOSFET) and MOSFET with the p-NiO floating field plate (PFFP MOSFET), the fabricated PSFP MOSFET achieves a BV of 2580 V at Nd = 3.5 × 1017 cm−3 and LGD = 25 μm, which is increased by 104% and 94%, respectively; the PSFP MOSFET obtains a power figure of merit of 46.87 MW/cm2, which is increased by 294% and 252%. It is expected that PSFP is a promising technological strategy to fulfill the potential of Ga2O3 for the high-efficiency power conversion.