Some benefits of Fe doped less dislocated GaN templates for AlGaN/GaN HEMTs grown by MOVPE

Strategies for maintaining a low threading dislocation density in highly resistive GaN layers grown by MOVPE on sapphire or SiC substrates using Fe modulation doping are presented. Sheet resistances as high as 10 8 Ω □ for dislocation densities lower than 8 × 10 8 cm –2 have been obtained. 2DEGs created at the AlGaN/GaN:Fe interface have good confinement while the low dislocation density benefits the mobility: room temperature values up to 2170 cm 2 V –1 s –1 have been obtained for a carrier density of 9.3 × 10 12 cm –2 . A simplified transport model is proposed to fit the experimental data. Processed transistors showed good channel control and DC performance. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)