MOSFETs have been fabricated in layers of laser-recrystallized poly-crystalline silicon on bulk, amorphous, fused quartz substrates, with the silicon film formed into device islands either before or after laser recrystallization. Field-effect mobilities as high as 320 cm2/V-sec have been obtained. The recrystallization is influenced by the different light absorption in the transparent substrate and in the absorbing silicon film.