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Proceedings Paper

Smart systems based on silicon carbide semiconductor technology for detection of combustible gas leakage in security applications
Author(s): Jenica Neamtu; Andrei Sorin Neamtu
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Paper Abstract

For high temperature sensing applications, metal/oxide/semiconductor (MOS) devices based on SiC show great promise, particularly above 200 °C, which represents an upper bound for MOS devices based on silicon (Si) semiconductor. This paper presents an investigation of a smart system based on silicon carbide technology used as hydrogen sensor at high temperature. The (Pd/SiO2/SiC) sensor was fabricated using microelectronics technology. The semiconductor used was 4H-SiC wafer, with two epitaxial layers: a buffer layer with a thickness of 0.5 μm and an active doped layer (ND=2.07x1016 cm-3) with a thickness of 8 μm. The silicon oxide (SiO2) layer, with 30 nm thickness was thermally grown by dry oxidation. The electrode of the capacitor was a catalytic metal, obtained by D.C. sputtering deposition of a palladium (Pd) thin film with 50 nm thickness. A chip structure with 400 μm diameter was obtained by photolithographic process.

The experiments were aimed at the electrical behavior of the M/O/SiC device at gas concentrations from 0 ppm to 2000 ppm H2 in argon (Ar). The C-V characteristics of the H2 sensor shift to smaller voltages with increasing gas concentration. The bias voltage shift is caused by hydrogen adsorption in metal-oxide and oxide-semiconductor interfaces. The flat band voltage has an important decrease when H2 concentration increases and reaches a -4.05 V shift at 2000 ppm H2 in Ar. These results show that the Pd/SiO2/SiC sensors are suitable for detection of small H2 concentrations (10-200 ppm H2), particularly for detection of H2 leakages.

Paper Details

Date Published: 8 October 2018
PDF: 10 pages
Proc. SPIE 10804, Advanced Manufacturing Technologies for Micro- and Nanosystems in Security and Defence, 108040P (8 October 2018); doi: 10.1117/12.2324964
Show Author Affiliations
Jenica Neamtu, National Institute for Research and Development for Electrical Engineering (Romania)
Andrei Sorin Neamtu, National Institute for Aerospace Research Elie Carafoli (Romania)

Published in SPIE Proceedings Vol. 10804:
Advanced Manufacturing Technologies for Micro- and Nanosystems in Security and Defence
Andrea Camposeo; Yuris Dzenis; Maria Farsari; Luana Persano, Editor(s)

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