SELF-ALIGNED METAL OXIDE TFT WITH REDUCED NUMBER OF MASKS

摘要

A method of fabricating MO TFTs on transparent substrates by positioning opaque gate metal on the front surface of the substrate defining a gate area, depositing gate dielectric material on the front surface of the substrate, overlying the gate metal and a surrounding area, and depositing metal oxide semiconductor material on the gate dielectric material. Depositing etch stop material on the semiconductor material. Positioning photoresist on the etch stop material, the etch stop material and the photoresist being selectively removable, and the photoresist defining an isolation area in the semiconductor material. Removing uncovered portions of the etch stop. Exposing the photoresist from the rear surface of the substrate using the gate metal as a mask and removing exposed portions so as to leave the etch stop material uncovered except for a portion overlying and aligned with the gate metal. Etching uncovered portions of the semiconductor material to isolate the TFT. Using the photoresist, selectively etching the etch stop layer to leave a portion overlying and aligned with the gate metal and defining a channel area in the semiconductor material. Depositing and patterning conductive material on the etch stop layer and on the semiconductor material to form source and drain areas on opposed sides of the channel area.