Low resistance transparent electrodes for large area flat display devices

Abstract

The dynamic performance of large area, high-resolution flat panel displays is contingent upon the conductivity of the transparent electrode. Electroplated copper and vacuum deposited aluminum bus bars attached to the sidewalls of conventional SnO2 electrodes offer theoretical improvements in conductivity while maintaining the electrode transmittivity. In association with a reactive ion etching process for delineating the tin oxide, auto registration methods for attaching copper by electroplating and aluminum by a resist lift off process are described, together with the achieved enhancement factors. A contact resistance between the aluminum and the tin oxide was found to significantly reduce the enhancement. The sidewall contact resistance lies between 0.4 and 4.0×104 Ω μm2, considerably lower than that previously reported for contacts to the tin oxide top surface. The enhancement factor for aluminum lies between two and three. The application of copper did not suffer from a contact resistance and an order of magnitude enhancement was obtained. We also report excellent adhesion, typically greater than 200 kg/cm2, of the metals to the tin oxide and identify the parametric space for achieving this.

Forming ohmic Ag/SnO2 contacts

“…For the sake of comparison, a similar diagram obtained for a gold-SnO 2 sample produced by vacuum evaporation of gold on a type-A sample is given in Fig. 3e, which is in agreement with the results reported by other researchers [11,17]. As shown in Fig.…”

“…Metal/SnO 2 contacts connecting the device structure to the outside circuitry are, almost in all cases, exposed to harsh environmental conditions and/or elevated temperatures [7,8], which necessitate utilization of noble metals. This is the main reason behind the investigations carried out on the electronic features of the platinum-, gold-, and silver-SnO 2 contacts [9][10][11]. Moreover, Ag/SnO 2 -based cermet segments have been proposed as contactor points [12] and studies on the electric conduction mechanism through the Ag/SnO 2 junctions may assist structure optimization in these high current density components.…”

“…Silver, at Φ m ¼ 4.4 eV [16], satisfies this criterion, and is advantageous owing to its $ 10 2 times lower price. However, a limited number of research articles on the current-voltage (I-V) characteristics of gold-and silver-SnO 2 contacts report observing various characteristics at different measurement conditions [11,14,17].…”

Synthesis and characteristics of SnO2 needle-shaped nanostructures

“…Tin oxide (SnO 2 ), an important and inexpensive semiconductor with a wide band gap (E g = 3.62 eV, at room temperature), is well known for its potential applications in gas sensors [1], transparent conducting electrodes [2], flat display devices [3], and solar cells [4]. While semiconductor crystals can be obtained in the nanometer length scale in various geometries [5,6], the onedimensional (1D) variants warrant special attention because the anisotropy in quantum confinement potentials can be used to produce unusual optical, magnetic, and electronic properties [7,8].…”

Mobility enhancement of p-type SnO2by In-Ga co-doping

“…Transparent conducting oxides (TCOs) are widely used in a variety of applications such as flat‐panel displays, solar cells, organic light emitting diodes (OLEDs), and electrochromic windows 1–4. Recently, much attention is still paid on TCOs, because they are one of the most promising materials for transparent electronic and optoelectronic devices.…”