Advanced Development for Defense Science and Technology

This SBIR Phase I project will show a novel architecture for silicon Thin Film (TFT) Field Effect Transistors (FETs), with a novel technology for manufacturing such FETs on wires. Arranged or “woven” into structured, flexible active matrix (AM TFT) arrays, they can enable a wide variety of applications; e.g. large area backplanes for next generation, low power flexible displays, or embedded into structural elements for prognostic monitoring. A simple 128 x 128 AM TFT demonstrator array will be built, with TFTs fully characterized to show polysilicon mobilities >30 cm2/Vs, and array flexibility to 0.5 in. bend radius in 2D, surpassing the general state-of-the-art in electron mobility for flexible AM TFT backplanes. Display backplanes, for example, are presently low mobility (<1cm2/Vs) amorphous silicon (a-Si:H) AM TFT arrays on rigid substrates (silicon or glass) made in huge, capital intensive fabs (in the Far East). While adequate for LCDs, they are barely adequate for small, low performance flexible displays (e.g. e-readers using electrophoretic frontplanes) and present significant challenges if integrated drivers, full video, high information content or color imagery and flexibility are needed, especially with increasing screen size. AM OLEDs, for example, are current driven, emissive arrays requiring high mobility polysilicon TFTs and very good pixel-to-pixel uniformity, but the industry has yet to develop commercially viable large area AM TFT backplanes on flexible substrates.