Materials Research Society Symposium Proceedings 468, 385 (1997).
Below is the abstract submitted to the meeting, not the abstract of the published paper:
Dry etched InAlN surfaces have been characterized by atomic force microscopy, current-voltage measurements and Auger Electron Spectroscopy. Electron Cyclotron Resonance discharges of BCl3, BCl3/Ar or BCl3/N2 are all found to produce nitrogen deficient surfaces that promote leakage current in rectifying metal contacts, with the BCl3/N2 producing the least disruption of the InAlN surface properties. During gate mesa plasma etching of InN/InAlN field effect transistors, the apparent conductivity in the channel can be either increased or decreased through three different mechanisms. If hydrogen is part of the plasma chemistry, hydrogen passivation of the shallow donors in the InAlN can occur. We find diffusion depths for 2H of ≥ 0.5 μm in 30 mins at 200°ree;C. The hydrogen remains in the material until temperatures ≥ 700°ree;C. Energetic ion bombardment in SF6/O2 or BCl3/Ar plasmas also compensates the doping in the InAlN by creation of deep acceptor states. Finally the conductivity of the immediate InAlN surface can be increased by preferential loss of N during BCl3 plasma etching, leading to poor rectifying contact characteristics when the gate metal is deposited on this etched surface. Careful control of plasma chemistry, ion energy and stoichiometry of the etched surface are necessary for acceptable pinch off characteristics.
This paper is part of Gallium Nitride and Related Materials II
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