Si-Ion Implantation Doping in β-Ga2O3and Its Application to Fabrication of Low-Resistance Ohmic Contacts

We developed a donor doping technique for β-Ga2O3 by using Si-ion (Si+) implantation. For the implanted Ga2O3 substrates with Si+=1×1019–5×1019 cm-3, a high activation efficiency of above 60% was obtained after annealing in a nitrogen gas atmosphere at a relatively low temperature of 900–1000 °C. Annealed Ti/Au electrodes fabricated on the implanted Ga2O3 layers showed ohmic behavior. The Ga2O3 with Si+=5×1019 cm-3 showed the lowest specific contact resistance and resistivity obtained in this work of 4.6×10-6 Ω·cm2 and 1.4 mΩ·cm, respectively.