Record Details
Modeling and characterization of amorphous oxide semiconductor thin-film transistors
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Modeling and characterization of amorphous oxide semiconductor thin-film transistors |
| Names |
Yeh, Bao-Sung
(creator) Wager, John (advisor) |
| Date Issued | 2015-03-11 (iso8601) |
| Note | Graduation date: 2015 |
| Abstract | The objective of the research presented herein is to elucidate the effect of traps in determining amorphous oxide semiconductor thin-film transistor (AOS TFT) performance using modeling and characterization. A novel method is proposed to extract the interface state distribution from a TFT transfer curve. Analysis of zinc-indium oxide (ZIO), zinc-tin oxide (ZTO), and indium-gallium-zinc oxide (IGZO) TFTs reveals an interface state distribution of ~10¹¹- 10¹² cm⁻² eV⁻¹ and that the interface state density is negligible compared to the density of free electrons in the accumulation layer beyond a surface potential of ~0.3 V. Technology computer-aided design (TCAD) simulation is employed in order to assess IGZO TFT non-ideal electrical characteristics involving different types of charge and/or traps. TCAD simulation reveals that negative charge placed at the backside (ungated) surface or frontside (gated) interface shifts a transfer curve to the right (left) because of depletion (accumulation) of the channel. A two-layer model attempts to address ultrathin channel layer trends. A new methodology for accomplishing capacitance-voltage (C-V) assessment of AOS channel layers is proposed. It is asserted that meaningful C-V analysis can only be accomplished using a quasi-static method and an insulating substrate. Properly conducted C-V measurements can be used to estimate the flat-band voltage, the effective donor density in an AOS channel layer, the channel layer surface potential, and the conduction band-tail state density and Urbach energy. |
| Genre | Thesis/Dissertation |
| Topic | Oxide Semiconductor |
| Identifier | http://hdl.handle.net/1957/55475 |
