Objective Liquid Crystal Displays (LCDs) have emerged to become the dominant flat-panel display technology in recent times. Their low power and voltage requirements are advantageous, not only for portability, but also because they lead to unstressed highly reliableelectronics which, when combined with the lack of inherent failure modes in LCDs, yield very thin lightweight displays with service lives orders of magnitude longer than Cathode Ray Tubes (CRTs). Thinfilm transistor addressing of LCDs allows an increasein display size and complexity to levels adequate for word processor and graphics displays. The aim of this project was to investigate a viable technology for the fabrication of large area (A5toA4) and complex (up to 1000addressable lines) LCDs based on polycrystalline and amorphous silicon transistor active matrices. Silicon Thin Film Transistors (TFTs) showed higher yield and reliability than other TFT materials. Extensive investigation of the following areas was made: -optimisation of transistor characteristics, yield and stability over large areas -special high throughput, large-area semiconductor processing equipment -special LCD fabrication techniques -colour systems -interactive displays -human factors. The aim of this project was to investigate a viable technology for the fabrication of large area and complex liquid crystal displays (LCD) based on polycrystalline and amorphous silicon transistor active matrices. Silicon thin film transistors (TFT) showed higher yield and reliability than other TFT materials. Extensive investigation of the following areas was made:optimisation of transistor characteristics, yield and stability over large areas;special high throughput, large area semiconductor processing equipment;special LCD fabrication techniques;colour systems;interactive displays;human factors.A breakthrough in the technology of polysilicon TFTs on glass allowed GEC to achieve, in a reproducible manner and in small-geometry (10x10micron) devices, on-off ratios in excess of 105, mobilities of 10cm2/Vs and threshold voltages as low as 8 V. Anew active matrix circuit was patented which entirely eliminates line failures and this increases the yield enormously. These breakthroughs were verified on test displays 6x4cm in size with 96x64pixels, which were fabricated with less than 10defect s. In the amorphous silicon (aSi) area, in addition to the CNET proprietary technology, ThomsonCSF developed an alternative potentially highyield process based on smallgeometry (10x20micron) highmobility (0.4-0.7cm2/Vs) TFTs and demonstrated almo st defect-free 6x8cm displays with 256x320pixels. CNET demonstrated an 8x8cm colour display with 320x320pixels based on a new RGB colour filter technology. A system based on capacitive interaction with resolution of 0.4mm was realised. AEG achieved very low pinhole density (1percm2) sputtered si licon dioxide. Modulex developed drive circuitry interconnections using high throughput tape automated bonding of chips on to flexible printed circuitboard. Significant achievements were also made in the areas of plasma silicon nitride and large area dis play photolithography. Following the end of the planned work schedule, a number of prototype displays were demonstrated at the ESPRIT Conference in September1987. A major follow-up project, which exploits the results achieved in these studies, is now going on in ESPRITprojectnumber2283. Exploitation Some recent surveys have underlined the importance of new display technologies because of their potential for eventually replacing CRTs as the principal visual display medium for a range of informatics based products. The progress on topics listed above places the collaborators in a strong position, even with respect to the Japanese competition, particularly because of the availability of both polysilicon and amorphous silicon technologies. Fields of science engineering and technologymaterials engineeringcolorsengineering and technologymaterials engineeringcoating and filmsnatural scienceschemical sciencesinorganic chemistrymetalloidssocial sciencespsychologyergonomicsengineering and technologymaterials engineeringliquid crystals Programme(s) FP1-ESPRIT 1 - European programme (EEC) for research and development in information technologies (ESPRIT), 1984-1988 Topic(s) Data not available Call for proposal Data not available Funding Scheme Data not available Coordinator GEC-Marconi Materials Technology Ltd EU contribution No data Address Elstree Way WD6 1RX Borehamwood United Kingdom See on map Total cost No data Participants (6) Sort alphabetically Sort by EU Contribution Expand all Collapse all AEG Olympia AG Germany EU contribution No data Address Goldsteinstraße 235 60528 Frankfurt am Main See on map Total cost No data ARISTOTELES UNIVERSITY OF THESSALONIKI Greece EU contribution No data Address 54006 THESSALONIKI See on map Total cost No data CNET France Télécom France EU contribution No data Address 2 route de Tregastel 22300 Lannion See on map Total cost No data MODULEX A/S Denmark EU contribution No data Address KLOEVERVEJ 101 7190 BILLUND See on map Total cost No data Thomson CSF France EU contribution No data Address Domaine de Corbeville 91404 Orsay See on map Total cost No data Università degli Studi di Bologna Italy EU contribution No data Address Viale Risorgimento 2 40136 Bologna See on map Total cost No data
