High hole concentration in nonpolar a-plane p-AlGaN films with Mg-delta doping technique

Abstract The Mg-delta-doping technique was employed in the epitaxial growth of the nonpolar a -plane p-AlGaN films on semi-polar r -plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). The structural, morphological, and electrical properties of the nonpolar a -plane p-AlGaN epi-layers were characterized with secondary ion mass spectroscopy (SIMS), high-resolution X-ray diffraction (HR-XRD), atomic force microscopy (AFM), and Hall effect measurement, respectively. The characterization results demonstrate that the crystalline quality, the surface morphology, and the efficiency of Mg incorporation in the nonpolar a -plane p-AlGaN films could be improved significantly by optimizing the pulse time of Cp 2 Mg mass flow in the Mg-delta-doping process. In fact, a hole concentration as high as 1.4 × 10 18  cm −3 under an average Mg incorporation density of ∼1 × 10 19  cm −3 was achieved.