High-dose Mn and Cr implantation into p-AlGaN films

摘要

Electrical and optical properties of p-AlGaN films grown by metalorganic chemical vapour deposition and implanted with high doses (3 x 10~(16) cm~(-2)) of 250 keV Mn and Cr ions are reported. Schottky diodes prepared on such implanted films after annealing at 700℃ show a strongly increased reverse leakage current and increased series resistance in the forward direction due to residual radiation damage related defects. The density of these defects was considerably higher for the Mn-implanted diodes which correlated with the higher expected radiation damage due to higher ion mass of Mn compared with Cr. Deep level measurements revealed the formation of hole traps with levels near E_υ + 0.4 eV and E_υ + 1 eV. Optical absorption measurements indicated the presence of two major defect bands at about 1,5-1.7 eV and 2.25-2.35 eV. The results are compared with earlier measurements on Cr- and Mn-implanted p-GaN films and on proton-implanted p-AlGaN films.