A new approach to thin film crystal silicon on glass: Biaxially-textured silicon on foreign template layers

We propose a new approach to growing photovoltaic-quality crystal silicon films on glass. Other approaches to film Si focus on increasing grain size in order to reduce the deleterious effects of grain boundaries. Instead, we propose aligning the silicon grains biaxially (both in and out of plane) so that (1) grain boundaries are ‘low-angle’ and have less effect on the electronic properties of the material and (2) subsequent epitaxial thickening is simplified. They key to our approach is the use of a foreign template layer that can be grown with biaxial texture directly on glass by a technique such as ion-beam-assisted deposition or inclined substrate deposition. After deposition of the template layer, silicon is then grown aligned to the template and subsequently thickened. Here, we outline this new approach to silicon on glass, describe initial experimental results and discuss challenges that must be overcome.