PERFORMANCE OF THIN HYDROGENATED AMORPHOUS-SILICON THIN-FILM TRANSISTORS

In this paper we have analyzed the influence of the mask channel length (L(M)) on the performance of the 55-nm-hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs), incorporating nitrogen-rich hydrogenated amorphous silicon nitride gate dielectric and phosphorus-doped microcrystalline silicon (n+ mu-c-Si:H) source/drain (S/D) contacts. In our TFTs the n+ mu-c-Si:H S/D contacts have a specific contact resistance around or below 0.5 OMEGA cm2. We have shown that in our TFTs a field-effect mobility and threshold voltage are dependent on L(M), and this dependence is most likely due to the influence of the S/D contact series resistance on TFTs characteristics. Finally, we have demonstrated that if the mask channel length is extended by a DELTA-L (which is a distance from the S/D via edge at which the electron injection/collection is taking place) the field-effect mobility and threshold voltage are independent of the channel length. In such a case mu-FE, V(T), and ON/OFF current ratio around 0.76 cm2/V s, 2.5 V, and 10(7), respectively, has been obtained.