Novel Tunnel-Contact-Controlled IGZO Thin-Film Transistors with High Tolerance to Geometrical Variability.
Advanced materials (Deerfield Beach, Fla.)
MetadataShow full item record
Sporea, R. A., Niang, K. M., Flewitt, A., & Silva, S. R. P. (2019). Novel Tunnel-Contact-Controlled IGZO Thin-Film Transistors with High Tolerance to Geometrical Variability.. Advanced materials (Deerfield Beach, Fla.), 31 (36), e1902551. https://doi.org/10.1002/adma.201902551
For the first time, thin insulating layers are used to modulate a depletion region at the source of a thin-film transistor. Bottom contact, staggered electrode transistors fabricated using RF-sputtered IGZO as the channel layer, with a 3 nm ALD Al₂O₃ layer between the semiconductor and Ni source-drain contacts show behaviours typical of source-gated transistors (SGTs): low saturation voltage (VD_SAT ~ 3V), change in VD_SAT with gate voltage of only 0.12 V/V and flat saturated output characteristics (small dependence of drain current on drain voltage). The transistors show high tolerance to geometry variations: saturated current changes only 0.15× for channel lengths between 2 - 50 μm, and only 2× for source-gate overlaps between 9 - 45 μm. A higher than expected (5×) increase in drain current for a 30K change in temperature, similar to Schottky-contact SGTs, underlines a more complex device operation than previously theorised. Optimizations for increasing intrinsic gain and reducing temperature effects are discussed. These devices complete the portfolio of contact-controlled transistors, comprising devices with: Schottky contacts, bulk barrier or heterojunctions, and now, tunnelling insulating layers. The findings should also apply to nanowire transistors, leading to new low-power, robust design approaches as large-scale fabrication techniques with sub-nanometre control mature.
External DOI: https://doi.org/10.1002/adma.201902551
This record's URL: https://www.repository.cam.ac.uk/handle/1810/294047
All rights reserved