Accession Number : ADA471261


Title :   Low-Cost Deposition Methods for Transparent Thin-Film Transistors


Descriptive Note : Doctoral thesis


Corporate Author : OREGON STATE UNIV CORVALLIS


Personal Author(s) : Norris, Benjamin J.


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA471261


Report Date : 26 SEP 2003


Pagination or Media Count : 188


Abstract : The objective of this dissertation is to introduce low-cost processing methods for the fabrication of ZnO transparent thin-film transistors "TTFTs". A novel method for depositing ZnO body layers via spin-coating of a zinc nitrate-based spin solution is presented. The processing conditions of spin-coated ZnO are optimized to produce continuous and polycrystalline thin-films. Optimal spin-coated ZnO thin-films are obtained for a 32 nm thick film which is converted to ZnO at 600?C in air. Spin-coated ZnO TTFT mobilities are consistently in the range of 0.1 - 0.2 cm2=V s. Spin-coating deposition methods for HfO2 are presented as a novel way to deposit low-cost gate insulators. Spin-coated HfO2 dielectric has a breakdown field, dielectric constant, loss tangent, and leakage current at 1 MV=cm of ? 2:1 MV=cm, 12.1?13.5, 0.411%, and 17.37 nA=cm2, respectively. Additionally, ZnO TTFTs constructed using spin-coated HfO2 gate insulators possess electrical characteristics similar to those obtained with aluminum oxide and titanium oxide superlattice "ATO" gate dielectrics. A second objective of this dissertation is to demonstrate a novel photolithography processing method for ZnO TTFTs with critical dimensions as small as 25 ?m. Lithography patterning of ZnO TTFTs is introduced as a means of assessing the effects of shrinking device dimensions on electrical performance.


Descriptors :   *THIN FILMS , *TRANSISTORS , LOW COSTS , DIELECTRICS , TRANSPARENCE , TANGENTS , POLYCRYSTALLINE , TITANIUM OXIDES , PHOTOLITHOGRAPHY , THICK FILMS , LITHOGRAPHY , FABRICATION , SUPERLATTICES


Subject Categories : ELECTRICAL AND ELECTRONIC EQUIPMENT


Distribution Statement : APPROVED FOR PUBLIC RELEASE