Low-leakage germanium-seeded laterally-crystallized single-grain 100-nm TFTs for vertical integration applications

We report on 100-nm channel-length thin-film transistors (TFTs) that are fabricated using germanium-seeded lateral crystallization of amorphous silicon. Germanium seeding allows the fabrication of devices with control over grain boundary location. Its effectiveness improves with reduced device geometry, allowing "single-grain" device fabrication. In the first application of this technology to deep submicron devices, we report on 100-nm devices having excellent performance compared to conventional TFTs, which have randomly located grains. Devices have on-off ratio >10/sup 6/ and subthreshold slope of 107 mV/decade, attesting to the suitability of germanium-seeding for the fabrication of high-performance TFTs, suitable for use in vertically integrated three-dimensional (3-D) circuits.