Low-temperature PECVD deposition of highly conductive n-type microcrystalline silicon thin films for optoelectronic applications

We report on the characterization results of doped n-type microcrystalline hydrogenated-silicon (µc-Si: H) films deposited by a plasma-enhanced chemical vapor deposition in the temperature range between 50 and 200°C. The interest in these films arises from their ability to combine a high optical absorption of amorphous silicon part with the electronic behavior of the crystalline silicon one, making them interesting for the production of large electronic devices such as solar cells, image sensors, and flat panels. It is demonstrated that n-type µc-Si: H films with high electrical conductivity can be obtained even at low temperature deposition, around 50°C (σ=12.8 Scm ⁻¹ ). The structural properties of the films have been studied by Raman and infrared spectroscopy that allowed for the determination of the crystalline fraction.