Titanium and aluminum-titanium ohmic contacts to p-type SiC

doi:10.1016/S0038-1101(97)00168-8

Solid-State Electronics

Volume 41, Issue 11, November 1997, Pages 1725-1729

https://doi.org/10.1016/S0038-1101(97)00168-8 Get rights and content

Abstract

Very low resistance ohmic contacts to p-type SiC were fabricated by depositing a 90-10 wt.% alloy of Al and Ti followed by a high temperature anneal of approximately 1000°C for 2 min. Specific contact resistances ranged from approximately $5 × 10^{−6} to 3 × 10^{−5} Ω cm^{2}$ on material with a doping of 1.3 × 10¹⁹ cm⁻³. The initial AlTi thickness before annealing was found to be critical to controlling the AlTi sheet resistance during the anneal. In addition, chemically etching the AlTi layer after annealing revealed pitting indicative of severe reaction between the AlTi and SiC surface, as confirmed by Rutherford Backscattering. In contrast, ohmic contacts to the same SiC material were fabricated by depositing pure Ti and annealing at 800°C for 1 min. These contacts were ohmic with a specific contact resistance between $2 × 10^{−5} and 4 × 10^{−5} Ω cm^{2}$ . Examination of the SiC surface after chemically etching away the annealed contact revealed a smooth surface, suggesting a much more planar Ti/SiC interface.

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Titanium and aluminum-titanium ohmic contacts to p-type SiC

Abstract

J. Cryst. Growth

Nuclear Instruments Methods B

Solid State Electron.

Ultramicroscopy

Solid State Electron.