Hydrogenated amorphous silicon germanium films doped with nitrogen (a-SiGe:H,N) to improve the long-wave infrared (LWIR) region absorption

Sensors in the long-wave IR region are used due to their enormous importance in technology for a variety of applications, as medical diagnostics, fire protection, automotive night vision, security and military, among others. This paper reports our study of hydrogenated amorphous silicon-germanium (a-SiGe:H) thin films deposited by low-frequency plasma-enhanced chemical vapor deposition (LF-PECVD), in order to be used as long-wave infrared (LWIR) sensing films in microbolometers. In order to improve the absorbance of the IR sensing films, they were doped with nitrogen (N-2) using different flow rates. FTIR measurements were performed to compare the absorption coefficient of the films doped with different N-2 flow rates, where was observed that effectively, the absorption in the 8 - 14 mu m spectral range was improved for the films deposited with larger N2 flow rates. Also, it was observed that the incorporation of N2 in the a-SiGe:H films improves the room temperature conductivity (sigma(RT)) up to 3 orders of magnitude.

Automated summary

This paper presents a study on the performance of hydrogenated amorphous silicon-germanium (a-SiGe:H) thin films deposited by low-frequency plasma-enhanced chemical vapor deposition (LF-PECVD) as long-wave infrared (LWIR) sensing films. The results show that increasing the nitrogen (N-2) flow rate improves the absorption coefficient of the films in the 8-14 μm spectral range, and the incorporation of N2 significantly enhances the room temperature conductivity.