Investigation on n-Type (−201) β-Ga2O3 Ohmic Contact via Si Ion Implantation

Heavy doped n-type β-Ga2O3 (HD-Ga2O3) was obtained by employing Si ion implantation technology on unintentionally doped β-Ga2O3 single crystal substrates. To repair the Ga2O3 lattice damage and activate the Si after implantation, the implanted substrates were annealed at 950°C, 1000°C, and 1100°C, respectively. High-resolution X-ray diffraction and high-resolution transmission electron microscopy show that the ion-implanted layer has high lattice quality after high-temperature annealing at 1000°C. The minimum specific contact resistance is 9.2 × 10⁻⁵ Ω. cm², which is attributed to the titanium oxide that is formed at the Ti/Ga2O3 interface via rapid thermal annealing at 480°C. Based on these results, the lateral β-Ga2O3 diodes were prepared, and the diodes exhibit high forward current density and low specific on-resistance.