Dose and implantation temperature influence on disorder produced by Ar+ ion implantation into GaN

In this work, we present a detailed investigation of disorder accumulation in gallium nitride (GaN) implanted with Ar⁺ ions as a function of implantation temperature and ion dose. Implantations were carried out with energy 150 keV in a dose range between 3 × 10¹⁴ and 3 × 10¹⁶ cm^-2 at a variety of substrate temperatures from room temperature to 1000°C. Depth distributions of the disorder were measured by Rutherford Backscattering spectrometry In the channeling mode and Ar depth profiles were obtained by Secondary Ion Mass spectrometry. Two disordered regions were identified in the damage depth distribution: a surface peak and a bulk damage peak. Both damage peaks exhibited a well-defined transition dose above which the damage level increased dramatically. With increasing implantation temperature up to 1000°C, the amount of damage in the surface peak decreased for the whole dose range studied. The amount of disorder in the bulk damage peak was less sensitive to the increase of implantation temperature and in addition displayed a ""reverse annealing"" behavior, which was attributed to the formation of characteristic secondary defects.