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A microbolometer fabrication process using polymorphous silicon–germanium films (pm‐Si x Ge y :H) as thermosensing material
Author(s) -
Calleja Cesar,
Torres Alfonso,
Moreno Mario,
Rosales Pedro,
SanzPascual María Teresa,
Velázquez Miguel
Publication year - 2016
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201532983
Subject(s) - materials science , temperature coefficient , microbolometer , plasma enhanced chemical vapor deposition , germanium , chemical vapor deposition , responsivity , silicon , electrical resistivity and conductivity , amorphous silicon , amorphous solid , analytical chemistry (journal) , bolometer , optoelectronics , crystalline silicon , optics , composite material , crystallography , photodetector , chemistry , electrical engineering , physics , chromatography , detector , engineering
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).