Effects of etching conditions on interface-treated trilayer junctions

Yang

Micro & Optical Tech Letters

et al. 2007

The laser assisted wet chemical etching technology was proposed in this study to apply in the etching of YBCO high temperature superconducting film, which was an intercrossing application involving superconducting electronics, laser technique, and chemistry. The etched surfaces and change characteristics were studied and some important experimental results were reported, including the influences of laser density, etching duration, and direction of LaAlO3 underlay on the etching characters of YBCO film under laser radiation. The main experimental results are as follows: the etching rate of YBCO film is accelerated dramatically under laser radiation and the rate is increased over time; the etching rate is relative with the laser power density; there is no strict boundary under the whole laser facula and the surface etching degree of YBCO film changes gradually; the etched surface characteristics are greatly influenced by the direction of LaAlO3 underlay. The laser assisted wet chemical etching technology of YBCO film can overcome the defect of common wet and dry ion etching technology, and probably becomes the main etching technology of YBCO film. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2672–2675, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22809

Section: Analysis and Design Of The Antennamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Surface character of laser assisted wet chemical etching of YBCO high temperature superconducting film

Yang

Micro & Optical Tech Letters

et al. 2007

Supercond. Sci. Technol.

“…Another candidate for controlling junction properties and reducing leakage paths is the incidence angle of an Ar ion beam (θ Ar ) in the etching process [11]. Figure 4 shows the θ Ar dependence of J c .…”

Section: Acc [V] Modulation Depth [%]mentioning

confidence: 99%

High-temperature superconductor vertically-stacked Josephson junctions

Yoshinaga

Kito

Izawa

et al. 2002

We study vertically-stacked interface-treated Josephson junctions (ITJs). The barriers of ITJs are formed by Ar ion etching and subsequent annealing, not by depositing an artificial barrier. We have investigated the dependences of the junction properties on the processing parameters. It is found that the control of junction properties can be realized by controlling the incidence angle of Ar, and that the higher accelerating voltage of Ar reduces leakage paths in a barrier. Moreover, we have successfully eliminated the excess current of the junctions using the PrGaO3 (PGO) doping process. We conclude that the conjunction of the interface treatment and the PGO doping technique leads to highly integrated Josephson circuits.

Supercond. Sci. Technol.

“…the average J c on one chip was ten times larger than the other chip. To improve the reproducibility of the junctions, we tried changing the processing parameters: accelerating voltage, etching time, annealing pressure and incident angle of the Ar ion [2,3]. However, the reproducibility was not sufficient.…”

Section: Introductionmentioning

confidence: 99%

Improvement of interface-treated junctions using vicinal SrTiO₃substrates

Yoshinaga¹,

Kito²,

Izawa³

et al. 2001

We have studied the improvement of vertically-stacked-structure Josephson junctions, employing both the interface-treated junction technique and flat YBa2Cu3O7-δ (YBCO) films using vicinal SrTiO3 (STO) substrates. The obtained film exhibited root-mean-square roughness of 2.3 nm, which was smaller than that of the films on normal substrates. We fabricated two chips in order to examine the reproducibility. We measured seven junctions on one chip. These junctions showed typical magnetic field modulation of the critical current density (Jc) of 83% at 4.2 K. The averaged Jc and the averaged normalized resistance (RnA) were 5.0×103 A cm-2 with a 1σ spread of 4.0% and 3.1×10-7 Ω cm2 with a 1σ spread of 6.4%, respectively. Thus junctions of small excess current with small spread were obtained. To examine the reproducibility of the junctions, we compared these junctions with those on the other chip, where the average Jc were 3.7×103 A cm -2. The results showed the improvement of the reproducibility by flat YBCO films using vicinal STO substrates.