Boron-doped hydrogenated mixed-phase silicon as thermo-sensing films for infrared detectors

• Published in: Materials science in semiconductor processing 2018-02, Vol.74, p.165-169
• Main Authors: Phong Pham, Duy, Park, Jinjoo, Shin, Chonghoon, Kim, Sangho, Nam, Yonghyun, Kim, Geunho, Kim, Minsik, Yi, Junsin
• Format: Article
• Language: English
• Subjects: Boron-doped; Hydrogenated silicon films; Infrared detectors; Micro-bolometers
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2017.10.034

Silicon materials have been widely used as thermo-sensing layers in infrared detectors or uncooled micro-bolometers. Parameters such as a large thermal coefficient of resistance (TCR), low sheet resistance (Rs), and low 1/f noise are important for high performance of these devices. However, there is always a trade-off between these parameters. For example, the crystalline silicon materials typically exhibit low Rs and 1/f noise, and significantly low TCR, while the amorphous silicon materials generally have large TCR, and considerably high Rs and 1/f noise. Consequently, the best trade-off can be achieved by using a mixed-phase structure of silicon materials, i.e. an intermediate form between the crystalline and amorphous structures. Herein we report the important characteristics of hydrogenated mixed-phase silicon films, deposited by the plasma-enhanced chemical vapour deposition process, for infrared detectors. The films in the mixed-phase structure showed high TCR values in the range of 2–3%K–1 and moderate sheet resistances in range of 10–40MΩsq−1. These results indicate that the mixed-phase silicon films are potential alternatives to conventional boron doped hydrogenated amorphous and microcrystalline silicon films for use as thermo-sensing layers in infrared detectors.