Transfer of a thin silicon film on to a ceramic substrate

In a scenario of large volume photovoltaic production, the cost of the Si starting substrate is almost 70% of the total module level cost. In such cases thin film crystalline silicon technology has large potential to reduce the cost of solar cells if a method to combine a high-quality Si film with a low-cost substrate is found. A process of transferring a thin porous silicon layer (PSL) onto a ceramic substrate like alumina is described. Separation of PSL from its parent Si substrate is obtained either by double porosity layer formation followed by high temperature annealing at 1050°C in H 2 or by carrying out electrochemical etching for a sufficiently long time at constant formation parameters. The transfer of PSL to alumina substrate is carried out using spin-on oxide or pyrolytic oxide as an intermediate layer. The quality of the transfer is checked by means of a scratch test. Reflectance characteristics of PSL transferred onto alumina substrate reveal an effective light passing.