Reduced Contact Resistance in GaN Using Selective Area Si Ion Implantation

We report selective area n-type doping using ion implantation of Si into semi-insulating, C-doped GaN samples activated using both conventional rapid thermal annealing (RTA) and 30 atm N ₂ overpressure annealing. Implanted regions were tested for Si activation using Circular Transmission Line Measurements (CTLM), while linear and circular photoconductive switches (PCSS) in the unimplanted regions were used as a test vehicle to separate implanted Si dopant activation from leakage paths generated by N vacancy formation due to damage and decomposition during annealing. We observed that at an optimal temperature around 1060 °C, a low contact resistivity of $1\times 10^{-6}\,\,\Omega $ -cm ² was obtained while preserving the breakdown of the unimplanted regions.