A microbolometer fabrication process using polymorphous silicon–germanium films (pm‐SixGey:H) as thermosensing material. Issue 7 (23rd April 2016)

• Record Type: Journal Article
• Authors: Calleja, Cesar; Torres, Alfonso; Moreno, Mario; Rosales, Pedro; Sanz‐Pascual, María Teresa; Velázquez, Miguel
• Is Part Of: Physica status solidi. Volume 213:Issue 7(2016:Jul.)
• Page Start: 1864
• Page End: 1868
• Publication Date: 2016-04-23
• Subjects: infrared detectors -- microbolometers -- polymorphous materials -- semiconductors -- SiGe -- thin films; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201532983
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : For uncooled resistive microbolometers, the properties that are necessary in the thermosensing materials in order to obtain high responsivity and detectivity are a high temperature coefficient of resistivity (TCR), low resistivity, and low noise. The most used materials for these applications are boron‐doped amorphous silicon (a‐Si:H, B) and amorphous silicon–germanium (a‐Si x Ge y :H), however, those materials present some drawbacks such as relatively low TCR values and poor stability. In this work, we performed the deposition and electrical characterization of hydrogenated polymorphous silicon–germanium films (pm‐Si x Ge y :H) deposited by plasma‐enhanced chemical vapor deposition (PECVD), using a standard frequency of 13.56 MHz. We found that these films have high values of activation energy ( E a = 6.2 eV), a thermal coefficient of resistance (TCR = 8% K −1 ), and room temperature conductivity ( σ RT = 2.38 × 10 −8 Ω −1 cm −1 ), which are superior characteristics to those of microbolometers based on a‐Si:H and a‐Si x Ge y :H films, contained in very large commercial infrared focal plane arrays (IRFPAs).