Trench formation method for releasing a substrate from a semiconductor template

A method for fabrication of a thin-film semiconductor substrate, the method comprising:

• forming a porous semiconductor layer on a reusable semiconductor template, said porous semiconductor layer conformal to said reusable semiconductor template;
• forming a thin-film semiconductor substrate on said porous semiconductor layer, said thin-film semiconductor substrate conformal to said porous semiconductor layer;
• forming an inner trench on said thin-film semiconductor substrate having a depth less than a thickness of said thin-film semiconductor substrate;
• forming an outer trench on said thin-film semiconductor substrate providing access to said porous semiconductor layer and positioned between said inner trench and an edge of said thin-film semiconductor substrate;
• and
• releasing said thin-film semiconductor substrate from said reusable semiconductor template.