Silicon MIS solar cells by anodization

Single crystal silicon MIS solar cells have been fabricated by the anodic oxidation, Anodization in the constant-voltage mode with formation voltage of 0.3 V was carried out in nonaqueous ethylene glycol solution. The thin insulating layer was annealed in hydrogen gas at 300 degrees C for 10 minutes. The composition of the thin insulating layer has been determined by XPS method and the interface state densities N-ss at the SiOx/Si interface has been calculated by Terman method. It was found that the open circuit voltage V-oc of MIS cells incereased compared with the Schottky barrier cells without reduction of the short current densities. Annealing process improved the composition of the thin insulating layer and decreased the N-ss. Compared with the as-grown MIS cells, the V-oc of the annealed MIS cells increased from 0.435 V to 0.525 V. This paper discusses the improvement of the anodic oxide film quality by annealing and its relation with the mechanism of increasing the V-oc.