Electronic transport mechanisms of nonalloyed Pt Ohmic contacts to p-GaN
- 8 May 2000
- journal article
- research article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 76 (19) , 2743-2745
- https://doi.org/10.1063/1.126462
Abstract
We report on the electronic transport mechanisms for nonalloyed Pt Ohmic contacts to p -GaN which were surfacetreated using a buffered oxide etch solution and (NH 4 ) 2 S x . Measurements show that the value of the effective Richardson constant (A ** ) is 12 A cm−2 K−2, which is considerably smaller than the theoretical value of 103.8 A cm−2 K−2. Based on Hall-effect results, the two-step surface-treated contact is modeled to consist of a Pt /p + -/p -GaN structure, and the conventionally treated contact consists of a Pt /p -GaN structure. The theoretical results obtained using these models are compared with the experimental data. It is shown that for the conventionally treated contact thermionic emission dominates the current flow, whereas for the two-step surface-treated contact, field emission is dominant.Keywords
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