No abstract

An amorphous silicon TFT particularly suited for the full color liquid crystal display driver has been developed and reported here. Various fundamental factors involved in the a-Si TFT, such as the effects of structure, materials, and the method of fabrications were reviewed and investigated in terms of the field effect mobility, the threshold voltage and the reliabilities. An inverted-staggered TFT structure was employed for the purpose wherein the interface states between two layers was successfully lowered by employing the successive deposition procedures of SiNx gate insulator on the a-Si layer. Proper ohmic contacts and the blocking of hole injections were accomplished by forming a n+ layer between the a-Si layer and the source/drain metal electrodes which consists of a double layer of Al/MoSi2 in order to prevent the aluminum diffusion into the a-Si layer during the 300°C heat treatment at the succeeding fabrication processes. The degradation of display images due to the high intensity backlights was minimized by employing a light shielding layer and by making the thickness of a-Si layer 200 Å against the direct sunlight of up to 100,000 luxes. Stable actual performances of TFT for more than 4000 hours at 80 °C were confirmed. The development of a color LCD TV driven by this TFT is also reported.

The spectral response of ZnSe-Zn1−xCdxTe (0⩽x⩽1) heterojunction is described. The heterojunction is formed by vacuum evaporation of ZnSe and Zn1−xCdxTe doped with In2Te3. The spectral response of this heterojunction is discussed for two cases, illuminated from the ZnSe side and from the Zn1−xCdxTe side. The theoretical results, based upon the assumption that the carriers excited by incident light are mainly transported by drift field, are in good agreement with the experimental results. Moreover, we could obtain a high internal quantum efficiency of 0.9 over the visible light range in this heterojunction.

No abstract

No abstract