Recovery of Dry Etching–Induced Damage in n-GaN by Nitrogen Plasma Treatment at Growth Temperature

The n-GaN films grown by metal-organic chemical vapor deposition (MOCVD) are etched in an inductively coupled plasma (ICP) reactor chamber. Atomic-force microscopy (AFM) characterization shows an increase of the surface roughness after the etching. Furthermore, Hall measurement and photoluminescence (PL) spectra highlight deterioration of the electrical and optical properties, respectively. Attempts to recover the damage are carried out by nitrogen plasma treatments accompanied by thermal annealing at the growth temperature in a molecular-beam epitaxy (MBE) chamber. Improved electrical and optical properties compared with those of the as-etched GaN, evidenced in both Hall and PL measurements, show a pronounced decrease of the damage introduced by the ICP etching.