Reduced Contact Resistance in GaN Using Selective Area Si Ion Implantation

Abstract

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 N2 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 $ -cm2 was obtained while preserving the breakdown of the unimplanted regions.