Lift-off of silicon epitaxial layers for solar cell applications

We have developed a technique which allows the fabrication of single crystalline layers of silicon of arbitrary size and shape and with a thickness ranging from less than 50 to greater than 100 μm. The films are grown by liquid phase epitaxy (LPE) on single crystal silicon substrates which have been patterned with a suitable masking layer material such as SiO₂. Detachment of the layers proceeds by etching through the regions where the epitaxial layer is attached to the substrate. In contrast to the technique utilised for the epitaxial lift-off of III-V compounds, this approach does not require an extremely selective etchant which etches a buffer layer while not attacking the epitaxial layer. The substrate can be re-used many times