Characterization and patterning of novel high-TCR Ta–Si–N thin films for sensor application

✍ Scribed by C.K. Chung; Y.L. Chang; J.C. Wu; J.J. Jhu; T.S. Chen

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 713 KB
• Volume: 156
• Category: Article
• ISSN: 0924-4247
• DOI: 10.1016/j.sna.2009.08.030

✦ Synopsis

Temperature coefficient of resistance (TCR) and resistivity of films are crucial factors for thermal resistive sensors and concerned with microstructure. In this paper, a Ta-Si-N thin film with high negative TCR of -6250 ppm/ • C at 30-100 • C has been fabricated on the silicon substrates by reactive co-sputtering at high nitrogen flow ratio (FN 2 % = FN 2 /(FN 2 + FAr) × 100%). It is larger than conventional materials, e.g. Pt, Cu, Ni and NiO x for thermal or flow sensors with TCR in the range of 2000-4540 ppm/ • C. The microstructure and crystallinity of Ta-Si-N films were examined by X-ray diffraction. The resistivity and TCR were measured by the four-point probe and Keithley 2400 multimeter. The resistivity decreases with increasing temperature for the nature of negative TCR. The magnitude of both resistivity and TCR increases with increasing FN 2 %. The patterning of high-TCR Ta-Si-N film on a flexible material has been performed by IC compatible processes, therefore it will be suitable for the integration with circuit design for the flexible sensor arrays in future.