4 inch Gallium Oxide Field-Effect Transistors Array with High-k Ta2O5 as Gate Dielectric by Physical Vapor Deposition

Abstract

Field-effect transistors (FETs) with ultra-wide bandgap semiconductor Ga2O3 have been fabricated by physical vapor deposition with advantages of low cost, wafer scale, and rapid production. The insulator-like pristine Ga2O3 is converted to semiconductor by co-sputtering Sn with post-annealing, which demonstrates a 5.6 × 10⁷ times higher on-state current. Importantly, this Sn-doped Ga2O3 sample shows a high breakdown voltage near 500 V. Furthermore, a 4 inch array of Sn-doped Ga2O3 FETs with high-k Ta2O5 gate dielectric has been fabricated on a silicon substrate, successfully showing a large on-current density of 1.3 mA mm⁻¹, a high ION/IOFF of 2.5 × 10⁶, and a low threshold voltage of 3.9 V, which are extracted from the average 350 devices. This work paves a promising way for Ga2O3-based nanoelectronics to serve medium-high voltage with low cost, rapid, and wafer-scale production.