Characterisation of nitrides by energy filtered TEM and EELS

The application of chemical microanalysis techniques to profile the reaction pathways of metallic diffusion couple ohmic contacts to AlGaN/GaN field effect transistors and to appraise the influence of As on the development of GaN heterostructures grown by plasma assisted molecular beam epitaxy is illustrated. 30 nm of Ti within AuPdAlTi contacts is necessary for TiN formation and contact activation following rapid thermal annealing at 950 °C, whilst the supply of excess Ti leads to over-development of the contact and consumption of the AlGaN layer. The presence of As during GaN growth leads to the development of a high density of cubic GaN stacking disorders. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)