Method of fabricating a thin film transistor with metal source and drain electrodes by diffusing impurities from a semiconductor layer

摘要

To provide a method of fabricating a thin film transistor which is capable of achieving a good ohmic contact between source and drain electrodes and a semiconductor layer, thereby solving problems of the conventional method.A first semiconductor layer containing impurities is formed on substantially oxygen-free metal source and drain electrodes. The impurities contained in the first semiconductor layer are allowed to diffuse into a substrate and the source and drain electrodes. An H2 plasma etching processing is performed to selectively etch the first semiconductor layer and a region of the substrate containing the impurities. A second semiconductor layer is formed on the source and drain electrodes. The impurities contained in the source and drain electrodes are allowed to diffuse into the second semiconductor layer, thus forming an ohmic contact layer.