Surface and interface properties of PdCr/SiC Schottky diode gas sensor annealed at 425°C
1998; Elsevier BV; Volume: 42; Issue: 12 Linguagem: Inglês
10.1016/s0038-1101(98)00217-2
ISSN1879-2405
AutoresLiang‐Yu Chen, Gary W. Hunter, Philip G. Neudeck, Dak Knight,
Tópico(s)Metal and Thin Film Mechanics
ResumoThe surface and interface properties of Pd0.9Cr0.1/SiC Schottky diode gas sensors both before and after annealing are investigated using Auger electron spectroscopy (AES), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). At room temperature the alloy reacted with SiC and formed PdxSi only in a very narrow interfacial region. After annealing for 250 h at 425°C, the surface of the Schottky contact area has much less silicon and carbon contamination than that found on the surface of an annealed Pd/SiC structure. Palladium silicides (PdxSi) formed at a broadened interface after annealing, but a significant layer of alloy film is still free of silicon and carbon. The chromium concentration with respect to palladium is quite uniform down to the deep interface region. A stable catalytic surface and a clean layer of Pd0.9Cr0.1 film are likely responsible for significantly improved device sensitivity.
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