The effects of thermal annealing either on the electrical activation of implanted species or device isolation were investigated. Silicon implantation was used for n-type doping, Magnesium for p-type doping and/or devices edge termination, while Nitrogen for devices isolation. The ions species were implanted on n-type GaN films (~ 2times10 16 cm -3 ) at energies between 30 and 180 keV and fluences in the range 0.1-5times10 14 cm -2 . After implantation, the samples were annealed in N 2 at high temperatures (ges1000degC) and different ramp rates (5 -100degC/min). Scanning Capacitance Microscopy (SCM) was used to estimate the electrical activation and/or determine the doping concentration profile in the implanted region. For n-type Si-implantation, annealing temperatures of 1200degC were necessary to achieve a significant electrical activation of the implanted specie. An active fraction of 63% was …