Effects of Mg accumulation on chemical and electronic properties of Mg-dopedp-type GaN surface

Tamotsu Hashizume
2003 Journal of Applied Physics  
Chemical and electronic properties of Mg-doped p-GaN surfaces were systematically investigated by x-ray photoelectron spectroscopy ͑XPS͒ and Auger electron spectroscopy ͑AES͒. The doping density of Mg ranged from 3ϫ10 19 to 9ϫ10 19 cm Ϫ3 . The XPS and AES analyses revealed the accumulation of Mg for all the air-exposed and chemically treated p-GaN surfaces. The apparent density of Mg calculated from the XPS integrated intensity and the AES intensity was more than one order higher than the value
more » ... gher than the value in bulk determined by secondary ion mass spectroscopy. Mg accumulation as well as large amounts of oxides made up the disordered region on the p-GaN:Mg surfaces. Large surface band bending of 1.2-1.6 eV was found at the p-GaN surfaces even after treatment in KOH and NH 4 OH solutions, due to the existence of high-density surface states. It was found that electron cyclotron resonance assisted N 2 -plasma treatment at 300°C for 1 min is very effective in removing such surface disordered regions and reducing surface band bending.
doi:10.1063/1.1580195 fatcat:ieq4bawp6bdr5lsuqnyvinjkkm