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Fabrication of GaN-Based Nanoscale Device Structures Utilizing Focused Ion Beam Induced Pt Deposition



Abhishek Motayed, Albert Davydov, Mark D. Vaudin, Igor Levin, John Melngailis, S N. Mohammad


In this work we have demonstrated nanoscale GaN device structures made from individual GaN nanowires and electrical contacts utilizing Focused Ion Beam (FIB) induced Pt deposition. These GaN nanowires were grown by direct reaction of Ga vapor with NH-(subscript 3) and had diameters ranging from 100 nm to 250 nm and lengths up to 200 microns. As-grown nanowires were dispersed on SiO_[subscript 2) coated p++ Si substrate. A 30KeV Ga(superscript +) ion beam was used to dissociate (Trimethyl)methylcyclopentadienyl-platinum precursor for depositing Pt contacts to GaN nanowires. FIB-deposited Pt contacts to GaN nanowires shown non-linear I-V characteristics, which turned linear after annealing at 500 degrees C for 30 s in argon. Resistivity of a GaN nanowire measured using a four-terminal contact geometry fabricated by depositing Pt with a FIB, was in the range of 5 x 10 (subscript 3) Ω.cm. Temperature dependent resistivity measurement of the GaN nanowire revealed semiconducting behavior with a weak temperature dependence of the resistivity. In this study both Ohmic and Schottky contacts to GaN nanowires have been realized with FIB deposited Pt contacts. Barrier height and ideality factor have been extracted for the metal-GaN nanowire Schottky junctions, which had low reverse breakdown voltage and large ideality factor of 18. Modulation of the current through the nanowire was achieved by applying a bias to the Si substrate acting as a backgate. N-type depletion mode behavior was observed in the GaN nano-transistor, which was consistent with the impurity related background concentrations expected in this type of growth method.
Journal of Applied Physics


GaN, metal contacts, nano-devices, semiconductor nanowires


Motayed, A. , Davydov, A. , Vaudin, M. , Levin, I. , Melngailis, J. and Mohammad, S. (2008), Fabrication of GaN-Based Nanoscale Device Structures Utilizing Focused Ion Beam Induced Pt Deposition, Journal of Applied Physics (Accessed June 14, 2024)


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Created October 16, 2008