Structure and electrical properties of boron doped hydrogenated mixed-phase silicon films for uncooled microbolometer

Abstract Boron doped hydrogenated silicon films used as thermo-sensing layers in infrared detectors or uncooled micro-bolometers are prepared by radio-frequency plasma-enhanced chemical vapor deposition (PECVD). In this work, we investigated TCR (higher the better) and sheet resistance, R sheet (lower the better), which are important factors for thermos-sensing layer used in uncooled microbolometer. The crystalline volume fraction (X c ) of films is controlled to get silicon films that satisfy the characteristics of high TCR and low R sheet . Through the control, amorphous, mixed- and microcrystalline phases were identified. As a result, the best TCR and R sheet were obtained in the mixed-phase. For the films, TRC is around 1–3%/K, R sheet is around 3–61.4 MΩ/□ and X c is around 7–17%. The 1/f noise is measured for various phases. It is found that 1/f noise of boron doped hydrogenated mixed-phase silicon (BMP-Si:H) is smaller than that of the amorphous phase. The results of BMP-Si:H films show that they are more suitable as thermos-sensing layers than boron doped hydrogenated amorphous silicon films.