A semiconductor-on-glass substrate having a relatively stiff (e.g. relatively high Young's modulus of 125 or higher) stiffening layer or layers placed between the silicon film and the glass in order to eliminate the canyons and pin holes that otherwise form in the surface of the transferred silicon film during the ion implantation thin film transfer process. The new stiffening layer may be formed of a material, such as silicon nitride, that also serves as an efficient barrier against penetration of sodium and other harmful impurities from the glass substrate into the silicon film.