Lift-off fabrication method for self-aligned thin film transistors

摘要

A method of fabricating a self-aligned thin film transistor (TFT) with a lift-off technique includes the steps of forming a multi-tier island on a semiconductive layer such that the island structure is disposed in a desired alignment over the gate electrode. The island structure includes a base layer portion, an intermediate body portion, and an upper cap portion, which overhangs the intermediate body portion by an amount between about 0.5 mu m and 1.5 mu m. Source and drain electrodes are formed such that the source/drain material is disposed over the semiconductive material up to the sidewalls of the base portion of the island structure, which base portion is patterned such that the source and drain electrodes are self-aligned with and extend a selected overlap distance over the gate to provide desired TFT performance characteristics. The upper cap layer is removed in a lift-off technique and the intermediate body portion of the island is removed to complete fabrication oft the TFT.