Properties of Germanium-Doped Indium Oxide Thin Films Prepared by DC Magnetron Sputtering

Abstract

Ge-doped indium oxide (In 2 O 3 ) thin films were prepared by dc magnetron sputtering. The electrical resistivity, 1.6 × 10 −4 ·cm, of the film deposited at 200 • C was obtained at 5.5% Ge doping. This was comparable with that of ITO (tin-doped In 2 O 3 ) films. Furthermore, amorphous films with Ge content higher than 5.0% were obtained when the substrate temperature was 20 • C, while they were obtained with Ge content higher than 7.0% when the substrate temperature was 200 • C. The electrical resistivity of 6.0% Ge-doped amorphous In 2 O 3 film deposited at 20 • C is 4.1 × 10 −4 ·cm. The etching rate of the film by 5% HCl is 1400 Å/min and is nine times as high as that of ITO films.

Influence of dopant segregation on the work function and electrical properties of Ge-doped in comparison to Sn-doped In2O3thin films

“…The IGO films presented in this work also exhibit a preferred orientation with only little dependence on deposition conditions. This is in good agreement with literature . The ionization potential of ITO and IGO films of 7.7 eV is higher than the one observed the corresponding surface .…”

“…The maximum electrical conductivity of IGO achieved in this work is (), which is close to that obtained for ITO in our previous studies (, ) and higher than the conductivity reported in literature . The lower conductivity compared to ITO is caused by the higher carrier concentration of ITO.…”

“…For these carrier concentrations (3–8), the mobility of IGO is higher than those of ITO. The highest mobility measured in this work for IGO amounts to , which is higher than values obtained by other groups . We like to note that potential surface accumulation layers will not contribute significantly to the total conductivity at such high carrier concentrations and a film thickness of .…”

“…At such high dopant concentration, part of the Sn‐donors are compensated by oxygen interstitials . Other dopants, which have been studied for are Zr , Mo , W , Ti , , and Ge . Although considerably higher carrier mobilities have been reported with most of these dopants, the obtained conductivities are still lower than those of optimized ITO.…”

Electronic Structures and Transport Properties of n-Type-Doped Indium Oxides

“…Substitutional replacement of one indium by a dopant atom represents a doping ratio of 6.25 at.%, which falls into the range of a typical experimental dopant concentration. 4,6,[13][14][15][16] The doping site at the 8b cationic position was found to be energetically more favorable, except for carbon, lead and iodine. 23 Long et al reported that the substitutional replacement of oxygen by carbon in cubic In 2 O 3 was possible.…”