David C. Paine

Strain-dependent electrical resistance of tin-doped indium oxide on polymer substrates

The increase in sheet resistance of indium–tin–oxide (ITO) films on polyethylene terephthalate with increasing tensile strain is reported. The increase in resistance is related to the number of cracks in the conducting layer which depends upon applied strain and film thickness. We propose a simple model that describes the finite but increasing resistance in the cracked ITO layer in terms of a small volume of conducting material within each crack.

Handbook of transparent conductors

Introduction to TC materials and their applicatons, key properties and needs.- Opto-electronic models of TC materials - the physics description.- Characterization of TC Materials.- TC device applications current and emerging.- In based TCOs.- Sn based.- Zn based.- Ternary, Quaternary and higher materials.- Organic TCs.- Non-conventional materials.- Transparent Electronics.- Nano-structured TCs (ZnO, TiO2, etc.).- Environmental and Economic Aspects.- Appendix. TCO properties and summary data

A study of low temperature crystallization of amorphous thin film indium–tin–oxide

Deposition of tin-doped–indium-oxide (ITO) on unheated substrates via low energy processes such as electron-beam deposition can result in the formation of amorphous films. The amorphous-to-crystalline transformation was studied in this system using in situ resistivity, time resolved reflectivity, glancing incidence angle x-ray diffraction, and transmission electron microscopy. The resistivity of 180 nm thick In2O3(9.9 wt. %SnO2) was monitored during isothermal anneals at 125, 135, 145, and 165 °C. The dependence of the resistance on the volume fraction of crystalline phase was established using glancing incidence angle x-ray diffraction and a general two phase resistivity model for this system was developed. These studies show that, upon annealing, as-deposited amorphous ITO undergoes both a structural relaxation and crystallization. Structural relaxation of the amorphous material includes local ordering that increases the ionized vacancy concentration which, in turn, increases the carrier density in the ...

A microstructural study of low resistivity tin-doped indium oxide prepared by d.c. magnetron sputtering

The microstructure of low resistivity (∼ 2 × 10−4 Ω cm) Sn-doped In2O3 (ITO) thin films prepared by multipass d.c. magnetron sputter deposition with an ITO (10 wt.% SnO2) target onto soda-lime glass substrates was investigated using plan-view and cross-sectional transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction. Each pass of the multipass sputter process deposits a 110 nm thick ITO layer. The substrate temperature was 400 °C during deposition and the sputter chamber was back-filled to a pressure of 1 × 10−3 Torr with a mixture of Ar and 0.8–1.0 at.% O2. Plan-view TEM studies combined with SEM observations of the film surface reveal that the sputtered ITO possesses a polycrystalline structure in which 200–350 nm grains are subdivided into highly oriented regions 10–30 nm in diameter. X-ray diffractometry studies show that the as-deposited films have a strong 〈100〉 texture and cross-sectional TEM studies reveal prominent columnar growth in the through-thickness direction.

High-mobility amorphous In2O3–10wt%ZnO thin film transistors

The authors report on the fabrication and characterization of thin film transistors that use sputter deposited amorphous indium zinc oxide both for the channel and source-drain metallizations in a gate-down configuration. The channel and source-drain layers were deposited from a single In2O3–10wt%ZnO ceramic target using dc magnetron sputtering onto an unheated substrate. The carrier densities in the channel (2.1×1017∕cm3) and source/drain regions (3.3×1020∕cm3) were adjusted by changing the reactive oxygen content in the sputter chamber during deposition. The resulting transistors operate as depletion mode n-channel field effect devices with saturation mobility of 20cm2∕Vs and on/off current ratio of 108.

Study of the effect of Sn doping on the electronic transport properties of thin film indium oxide

High quality, low resistivity (2.6×10−4 Ω cm), 0.32‐μm‐thick amorphous and polycrystalline, pure and Sn‐doped, In2O3 films prepared by high density plasma‐assisted electron beam evaporation were used to investigate the effect of Sn doping on the electronic transport properties of this material. Amorphous films with high carrier density in the as‐deposited state showed no effect of Sn doping on resistivity (ρ), Hall mobility (μ), or carrier density (n) over the range 0 to 5.3 wt % Sn. After recrystallization by annealing in air at 180 or 250 °C for 20 min, n, μ, and ρ were seen to be strongly dependent on Sn concentration in the range 0 to 1.5 wt % with a decreasing effect of Sn doping in the range 1.5 to 5.3 wt %. The data presented in this study were analyzed based on charged and neutral impurity scattering models and suggest that increasing Sn concentration leads to the formation of defect complexes which act as scattering centers but which do not contribute carriers to the material.

Visible photoluminescence from nanocrystalline Ge formed by H2 reduction of Si0.6Ge0.4O2

Samples of nanocrystalline Ge embedded in SiO2 that display visible photoluminescence were synthesized from chemical vapor deposition‐grown Si0.6Ge0.4 in a two step process of hydrothermal oxidation using steam at 25 MPa and 475 °C followed by annealing at 750 °C in flowing forming gas (80/20:N2/H2). A broad photoluminescence band, peaked at 2.14 eV (580 nm) with a full width at half maximum of 0.3 eV, was observed in samples that were annealed at 750 °C in flowing forming gas for 10, 30, and 60 min. As‐oxidized (i.e., unprecipitated) samples show no photoluminescence peak when excited under identical conditions.

The growth of strained Si 1− x Ge x alloys on 001 silicon using solid phase epitaxy

In this paper we report on the growth of pseudomorphically strained Si 1− x Ge x alloys on 〈001〉 Si by solid phase epitaxy. One set of amorphous alloys was formed by high dose ion implantation 74 Gc implanted at an energy of 200 kcV to a fluence of 9.6 ⊠ 10 20 /m 2 ). Our TEM observations show that regrowth of these Si 1− x Ge x ( x max = 0.14) films at ≍590°C results in a high density of planar defects and that these defects are associated with faceting of the amorphous/crystalline interface during annealing. These results were compared with the solid phase regrowth of MBE-grown Si 0.7 Ge 0.3 amorphized with 170 keV 28 Si ions which exhibited identical defects and faceting during regrowth. Attendant with this faceting was a decrease in the regrowth velocity, a result of a change from a planar {001} growth morphology to a multi-faceted growth surface containing many in situ TEM experiments. It was shown that the regrowth rate at 594°C in pure Si was 51 nm/min, whereas in the Si 0.7 Ge 0.3 the regrowth rate decreased, as a result of {111} faceting, to 21 nm/min. RBS was used to characterize Ge concentrations and lattice resolution TEM was used to study the development of the faceted interface and associated planar defects during regrowth.

Oxidation of Si1−xGex alloys at atmospheric and elevated pressure

The oxidation of alloys of Si1−xGex differs significantly from that of pure Si in both the thermodynamics of the process and in the kinetics of the oxidation reaction. In this paper these fundamental differences are explored and are used to explain experimental observations of Si1−xGex oxidation that are presented herein and elsewhere in the literature. Alloys of Si1−xGex (with x=5.4, 11.6, and 17 at. %) approximately 200 nm thick were oxidized using the following two processes: (i) dry oxygen at 680 atm at a temperature of 550 °C and (ii) conventional, 1‐atm steam at 800 °C. The wet oxidation conditions were chosen to produce an oxide thickness comparable (≊100 nm for xGe=11.6 at. %) to that obtained during high‐pressure oxidation at 550 °C. Auger sputter depth profiling, x‐ray photoelectron spectroscopy (XPS), and cross‐sectional transmission electron microscopy were used to characterize the as‐grown oxides. XPS studies reveal that high‐pressure oxides formed from alloys of Si1−xGex chemically incorpora...

Study of the effect of ion implantation on the electrical and microstructural properties of tin-doped indium oxide thin films

Ion implantation of H2+ or O+ ions in the range 0–1.7×1015 and 0–1.3×1015/cm2, respectively, was used to investigate the effect of implant‐induced damage on the electrical properties of Sn‐doped In2O3 (ITO) films deposited by electron‐beam evaporation on SiO2‐coated soda‐lime glass substrates. The films were characterized as a function of implant dose using low‐temperature Hall effect, resistivity, optical transmissivity, x‐ray diffraction, and transmission electron microscopy (TEM). A systematic decrease in both carrier density (n) and Hall mobility (μ) was observed with increasing dose of either implant species. The electronic results were analyzed using charged and neutral impurity scattering models which suggest that the observed changes are due to the degradation of electrically active donor centers and the generation of the neutral scattering centers. The microstructure of the implanted films, as revealed by TEM and x‐ray diffraction, is consistent with the presence of significant dynamic recovery d...