Optical and electrical characterization of crystalline silicon films formed by rapid thermal annealing of amorphous silicon

Publication date: Available online 15 January 2016
Source:Thin Solid Films
Author(s): Christopher Baldus-Jeursen, Roohollah Samadzadeh Tarighat, Siva Sivoththaman
The effect of rapid thermal annealing (RTA) on n-type hydrogenated amorphous silicon (a-Si:H) films deposited on silicon wafers was studied by electrical and optical methods. Deposition of a-Si:H films by Plasma Enhanced Chemical Vapor Deposition (PECVD) method was optimized for high deposition rate and maximum film uniformity. RTA processed films were characterized by Spreading Resistance Profiling (SRP), Hall effect, Spectroscopic ellipsometry (SE), defect etching and Transmission electron microscopy (TEM). It was found that the films processed between 600 °C and 1000 °C were highly crystalline and that the defect density in the films diminished with increasing thermal budget. Junctions formed by the RTA processed n-type a-Si:H films on p-type Si wafers were tested for device applicability. It is established that these films can be used as the emitter layer in n⁺ p photovoltaic (PV) devices with over 14% conversion efficiency.