Carrier activation in Mg implanted GaN by short wavelength Nd:YAG laser thermal annealing

Abstract

Activation of Mg‐implanted GaN has been investigated by the combination of thermal and laser annealing. The laser annealing was carried out using third harmonic generation (λ = 355 nm) of a Nd:YAG laser. Mg ion activation and reduction of implanted‐defects after various annealing processes have been analyzed with Raman spectroscopy. The sample that was thermally annealed at 700 °C for 20 min; followed by laser annealing, with energy density of 0.35 mJ cm−2, is found to be effective for p‐type conversion in electrical characteristics. The value for sheet resistance and hole mobility is 1.7 × 103 Ω/□ and 40 cm2 Vs−1; respectively. Positron annihilation revealed that the vacancy clusters created in the sub‐surface region, by thermal annealing dissolved following laser annealing, leading to the p‐type conversion of GaN.