Thickness Dependences of Resistivity and Temperature Coefficient of Resistance for Ge Thin Films Sandwiched between Si Layers for Uncooled Infrared Imaging Sensor

• Published in: Japanese Journal of Applied Physics 2011-12, Vol.50 (12), p.125801-125801-4
• Main Authors: Yamaki, Kazuhiro, Tai, Takashi, Kinoshita, Junichi, Sekino, Shoji, Nakamura, Shin, Yoshitake, Tsutomu, Furukawa, Akio
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.50.125801

An RF magnetron sputtering technique was used to deposit Ge and stacked Si/Ge films for infrared imaging sensors; the electrical characteristics of these films were estimated. The cross-sectional scanning electron microscope (SEM) image obtained confirmed that a layered Si/Ge structure was deposited on the SiO 2 substrate. The layered film, annealed in an Ar atmosphere, exhibited a large temperature coefficient of resistance (TCR) ($-3.63$%/K) and a low resistivity (64.5 $\Omega$$\cdot$cm). The conductivity and TCR of Si/Ge films depend on the thickness of the Ge layer. A significant improvement in TCR was achieved by decreasing the thickness of the Ge layer. Ge thin films sandwiched between amorphous silicon layers facilitate the realization of a noncooled bolometer.