Low temperature amorphous growth of semiconducting Y–Ba–Cu–O oxide thin films in view of infrared bolometric detection

• Published in: Thin solid films Vol. 520; no. 14; pp. 4754 - 4757
• Main Authors: Jagtap, Vishal S., Dégardin, Annick F., Kreisler, Alain J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2012; Elsevier
• Subjects: Absorption coefficient; Amorphous semiconductor; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; Infrared uncooled thermal detector; Low temperature sputtering deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical band gap; Optical conductivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Structural properties; Theory and models of film growth; Yttrium barium copper oxide; Low temperature sputtering deposition; Infrared uncooled thermal detector; Absorption coefficient; Optical band gap; Amorphous semiconductor; Yttrium barium copper oxide; Structural properties; Optical conductivity; Photonic band gap; Electrical conductivity; Amorphous thin film; Roughness; Infrared detection; Bolometers; Nanostructures; Absorption coefficients; Sputtering; Thin films; Optical properties; High-Tc superconductors; Barium Copper Yttrium Oxides Mixed; Infrared detectors; Electrical properties; Amorphous semiconductors; Granular structure; Electrical measurement; Growth mechanism; Sputter deposition; Lowtemperature sputtering deposition
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2011.10.127

YBa2Cu3O6+x (YBCO) compounds are well known to exhibit superconducting properties for x>0.5 and semiconducting properties for lower oxygen content. In this work, YBCO oxide thin films of the semiconducting phase were deposited by direct-current (DC) hollow cathode sputtering at low temperature in the 100 to 400°C range. Structural, electrical and optical properties are investigated and discussed in relation with the envisaged bolometric detection application. Structural characterizations show that films are amorphous, with a granular structure of low roughness (3nm rms). DC electrical measurements both reveal that films grown at 100°C exhibit a high temperature coefficient of resistance (TCR~−3%K−1 to −4%K−1 at 300K) and an optimized low resistivity value of 345Ω·cm at 300K. Consequently, this material is suitable for uncooled infrared bolometer application and can be deposited at 100°C in a complementary metal-oxide-semiconductor compatible technological process for co-integration with readout circuitry. In addition, optical measurements performed in the 0.5 to 2.2μm wavelength range on films grown at 100°C highlight optical conductivity values in line with those expected for YBCO material, as well as the presence of two optical band gaps that are discussed with respect to the film nanostructure.