Effect of growth termination conditions on the performance of AlGaN/GaN high electron mobility transistors
- 14 May 2001
- journal article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 78 (20) , 3088-3090
- https://doi.org/10.1063/1.1372620
Abstract
The effect of the growth conditions of the top 2.5 nm thick AlGaN cap layer and wafer cool down conditions on AlGaN/GaN high electron mobility transistor performance was investigated. The AlGaN/GaN heterostructures were deposited on sapphire by metalorganic chemical vapor deposition and consisted of a 3 μm thick semi-insulating GaN layer and an 18 nm thick Al0.33Ga0.67N layer, the top 2.5 nm of which was deposited under various conditions. The power performance of the devices severely degraded for all samples where the Al content of the top 2.5 nm of AlGaN was increased and/or the ammonia flow during growth of the top layer was decreased. A modest improvement in the output power density was observed when the growth conditions of the cap layer were identical of those of the rest of the AlGaN layer, but when the wafer was cooled down in pure nitrogen.Keywords
This publication has 10 references indexed in Scilit:
- Gallium nitride based high power heterojunction field effect transistors: process development and present status at UCSBIEEE Transactions on Electron Devices, 2001
- The impact of surface states on the DC and RF characteristics of AlGaN/GaN HFETsIEEE Transactions on Electron Devices, 2001
- Polarization effects, surface states, and the source of electrons in AlGaN/GaN heterostructure field effect transistorsApplied Physics Letters, 2000
- The effect of surface passivation on the microwave characteristics of undoped AlGaN/GaN HEMTsIEEE Electron Device Letters, 2000
- Transient processes in AlGaN/GaN heterostructurefield effect transistorsElectronics Letters, 2000
- Metalorganic chemical vapor deposition of high mobility AlGaN/GaN heterostructuresJournal of Applied Physics, 1999
- Polarization-induced charge and electron mobility in AlGaN/GaN heterostructures grown by plasma-assisted molecular-beam epitaxyJournal of Applied Physics, 1999
- Influence of N2 carrier gas on surface stoichiometry in GaN MOVPE studied by surface photoabsorptionJournal of Crystal Growth, 1998
- Spontaneous polarization and piezoelectric constants of III-V nitridesPhysical Review B, 1997
- Bias dependent microwave performance of AlGaN/GaN MODFET's up to 100 VIEEE Electron Device Letters, 1997