Deposition and characterization of polymorphous germanium films prepared by low frequency PECVD

In this work we have deposited polymorphous germanium (pm-Ge:H) thin films by low frequency plasma enhanced chemical vapor deposition (LF-PECVD). We have studied the effect of the deposition pressure on the structural and electric characteristics of the films. Atomic force microscopy was used to analyze the surface roughness of the pm-Ge:H films, while transmission electron microscopy was used to observe the cross section.The temperature dependence of conductivity (σ(T)), deposition rate (Vd), activation energy (Ea) and the temperature coefficient of resistance (TCR) were extracted on the pm-Ge:H films deposited at different pressure values. An optimal pressure range was found, in order to produce pm-Ge:H films with high Ea and TCR which are key parameters for thermal detection applications.

► We have deposited and characterized polymorphous germanium (pm-Ge:H) prepared by LF-PECVD.
► At present there is no work related to the study of pm-Ge:H as thermo-sensing element.
► We aim to use pm-Ge:H as thermo-sensing film on IR detectors (micro-bolometers).
► The deposition pressure was varied in order to observe its effect on the pm-Ge:H film characteristics.