Abstract
Optimization of GaN channel conductivity in AlGaN/GaN Heterojunction Field Effect Transistor (HFET) structures was performed using High Resistivity (HR) GaN templates grown by Metal-organic Vapor Phase Epitaxy (MOVPE). The GaN sheet resistance was tuned using final nucleation layer (NL) annealing temperature. Using an annealing temperature of 1033 °C, GaN with sheet resistance of 1010 Ω/sq was achieved, comparable to that of Fe-doped GaN. X-Ray Diffraction (XRD) and Photoluminescence (PL) analysis show that the high resistance GaN is achieved due to compensating acceptor levels introduced through edge-type threading dislocations. XRD analysis also shows optimization of annealing temperature provided a means to maximize GaN sheet resistance without significantly degrading material quality. AlGaN/GaN HFET layers grown using HR GaN templates gave surface and interface roughness of 14 and 7 À, respectively. The 2DEG Hall mobility and sheet charge of HFETs grown using HR GaN templates was comparable to similar layers grown using unintentionally doped (UID) GaN templates.
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Acknowledgements
Work supported by NSF/NASA/EPRI (Contract No. ECS 0233500), ONR (Contract No. N00014-02-1-0128) and NASA GSRP (Contract No. NGT-52339) and NASA NGT3-52372.
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Hubbard, S.M., Zhao, G., Pavlidis, D. et al. Optimization of GaN Channel Conductivity in AlGaN/GaN HFET Structures Grown by MOVPE. MRS Online Proceedings Library 831, 114–119 (2004). https://doi.org/10.1557/PROC-831-E11.11
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DOI: https://doi.org/10.1557/PROC-831-E11.11