Fabrication methods for making thin film devices on transparent substrates are described. Gate, source, and drain electrodes of a transistor are formed on a transparent substrate. The widths of the drain electrode and source electrodes are greater than a width of the gate electrode. A dielectric layer is formed on the gate electrode. A semiconductor layer is deposited proximate to the gate, source and drain electrodes. Photoresist is deposited on the semiconductor. The photoresist is exposed to light directed through the transparent substrate so that the gate electrode masks the photoresist from the light. The semiconductor layer is removed in regions exposed to the light.