Carrier profiles in Fe doped GaN layers grown by MOVPE

Continuously-doped and modulation-doped GaN:Fe layers were grown by MOVPE using a 2-step process, that promotes first 3D then 2D growth, allowing to achieve low dislocations densities. Two characterization methods were used to analyse the electrical compensation in GaN:Fe. A first study by Hall effect have been performed down to the sapphire substrate thanks to reactive ion etching steps. The local electrical response of GaN:Fe has also been investigated by cross-sectionnal Electrostatic Force Microscopy (EFM), showing that GaN:Fe is efficiently compensated in the first 0.5 to 2 micron next to the substrate. From these measurements it appears that Fe-doping is more efficient when Fe is incorporated in the GaN grown in a 3D than in a 2D growth-mode. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.