**5. Conclusions**

In summary, some alternatives to improve the metal-semiconductor interface are analysed. An over-etching at the source/drain regions of the active layer can improve the TFT electrical performance, since this process gets close the n+ contact layer and the electron induced-channel. Moreover, the plasma-induced damage by the over-etching process is reduced after the application of a hydrogen plasma. On the other hand, the planarized TFTs exhibit better performance due mainly to the improved contact resistance. The simulations show an increase in the conduction band energy in the a-SiGe:H film at the metal-semiconductor interface. This increase acts as a barrier for the electrons, which results in an apparent increase of contact resistance. Finally, the influence of the metal-semiconductor interface in the electrical stability of TFTs is presented. Although the compared TFTs present the same insulator-semiconductor interface, the fabrication of the metal-semiconductor interface plays an important role in the electrical stability of these devices.
