Compositional tuning of atomic layer deposited MgZnO for thin film transistors

Abstract

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Atomic layer deposition of Nb-doped ZnO for thin film transistors

“…However, as the Nb cycle percentage increases, the films become amorphous while shifting the band gap to higher energies. Optimum TFT performance was achieved with 175 C 3.8% NbZnO where the l sat is superior to ALD ZnO doped with Mg 9 and Si. 8 See supplementary material for XPS CL spectra of bulk Nb 2 O 5 O 1s and the effects of annealing in air on 12.5% NbZnO O 1s.…”

“…Research into non-indium based ZnO materials for TFT application includes: gallium, 7 silicon, 8 and magnesium. 9 These dopants act as effective oxygen vacancy (V o ) suppressors and can further increase the band-gap of the ZnO through the Burstein-Moss effect. [7][8][9] Niobium (Nb) has the potential as a dopant, due to its high valency (Nb 5þ ) which offers the prospect of a V o suppressor, superior to the dopants gallium (Ga 3þ ), silicon (Si 4þ ), and magnesium (Mg 2þ ).…”

“…9 These dopants act as effective oxygen vacancy (V o ) suppressors and can further increase the band-gap of the ZnO through the Burstein-Moss effect. [7][8][9] Niobium (Nb) has the potential as a dopant, due to its high valency (Nb 5þ ) which offers the prospect of a V o suppressor, superior to the dopants gallium (Ga 3þ ), silicon (Si 4þ ), and magnesium (Mg 2þ ). Furthermore, Nb can act as an effective substitutional dopant for Zn 2þ and subsequently reduce the disorder and carrier scattering.…”

Physical and electrical characterization of Mg-doped ZnO thin-film transistors

“…We recently published work on doping ratios of Mg and ZnO using atomic layer deposition (ALD) [6] where the optimum thin-film transistor (TFT) performance obtained was achieved with a cycle ratio of 7:1. X-ray diffraction indicated that the film crystallinity remained constant whilst varying the Mg content.…”

“…However, indium is a rare element and is known to suffer from large price fluctuations, hence, limiting its potential to dominate the transparent conductive oxide (TCO) market. Alternative dopants for ZnO such as F [3], Li [4] Mo [5] and Mg [6][7] have been implemented to improve the electrical characteristics of the films.…”