Superconductor technology: apparatus – material – process – High temperature devices – systems – apparatus – com- ponents,... – Semiconductor thin film device or thin film electric...
Patent
1993-12-23
1995-05-30
King, Roy V.
Superconductor technology: apparatus, material, process
High temperature devices, systems, apparatus, com- ponents,...
Semiconductor thin film device or thin film electric...
505190, 505193, 505329, 505330, 505701, 505702, 505729, 134 38, 427 62, 4274192, 4274193, 427 63, 257 34, 257 39, H01L 23485, H01L 3900
Patent
active
054201012
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a national phase of PCT/DE92/00518 filed 28, Jun. 1992 as based upon German National applications P4120766.1 of 24 Jun. 1991 and P4204370.0 of 14 Feb. 1992 under the International Convention.
1. Field of the Invention
The invention relates to structured conductive tracks and to a process for producing structured conductor tracks of high temperature superconductor (HTSC) layers.
2. Background of the Invention
A focal point of development activity in the field of HTSC technology is the production of HTSC structures from thin superconductive layers ["films"]. To produce such structures two processes mainly have been developed in recent years.
In the customary process, an HTSC film is deposited by laser ablation, sputtering or the like upon a substrate which is suitable for monocrystalline growth of the HTSC. Thereafter a lacquer layer is additionally applied to the HTSC film in the regions provided for the HTSC structure, exposed and developed. The lacquer surfaces protect the coated superconductive surfaces from a subsequent etching step by means of which the HTSC film is again removed from the substrate in those regions not protected by the lacquer mask. This etching process can be effected wet chemically or by ion-beam etching. After removal of the lacquer layer, the end product of this process has a structured HTSC film running along the substrate surface.
The desired superconductive characteristics are associated with the exact chemical composition and crystallinity of the HTSC film remaining after the etching step. Nevertheless, especially in the surface regions of the HTSC structure, high electrical fields and strong surface currents can be expected. A drawback of the described process is that even the structured HTSC film is degraded by the etching step at the accessible and therefore unprotected lateral surfaces.
This is the consequence of disrupting the stoichiometry and crystallinity of the HTSC film above all in these upper surface regions so that the surface currents are intercepted by a poor partly receptive material.
As a consequence there is a reduction in the desired superconductive-properties of the HTSC tracks [traces]. In addition the lacquering also can detrimentally affect the horizontal surfaces of the superconductor.
In order to avoid such a degradation of the structured HTSC film by etching, a further process, the so-called "inhibit process" has been developed.
In the latter, initially a lacquer layer is applied to the substrate in the surface regions which are to carry the structured HTSC film. Then an inhibit doping material is vapor-deposited over the entire upper surface, whereby in the substrate surface regions intended for the HTSC tracks, the lacquer mask is separated from the substrate. In a subsequent lift-off process, the lacquer mask and the doping material simultaneously found upon the lacquer mask are lifted from the regions of the future structured HTSC films of the substrate. The HTSC film is deposited in the next step upon the now doped and undoped upper surface regions of the substrate. The deposition is effected as a rule at relatively high substrate temperatures of about 500.degree. C. to 800.degree. C. The HTSC material can, however, also be applied at lower temperatures; in any case one must then follow with an annealing step at the indicated higher temperatures.
The structured HTSC film then develops by monocrystalline growth upon the undoped substrate regions, while upon the doped upper surface, the HTSC material, by vertical diffusion of the doping substance, becomes an insulator.
In addition there develops apart from this desired vertical diffusion also a lateral diffusion of the doping substance into the superconductive structure because the developing monocrystalline HTSC tracks are laterally in direct contact with the doping substance. The lateral diffusion of the doping substance in the structured HTSC film has the consequence that within the conductive tracks there is a concentration gradient of
REFERENCES:
patent: 5096882 (1992-03-01), Kato et al.
patent: 5215960 (1993-06-01), Tanaka et al.
patent: 5229360 (1993-07-01), Shiga et al.
patent: 5236896 (1993-08-01), Nakamura et al.
patent: 5292717 (1994-03-01), Roas
Buchal Christoph
Copetti Carlo
Schubert Jurgen
Zander Willi
Dubno Herbert
Forschungszentrum Julich GmbH
King Roy V.
LandOfFree
Structures super conductor tracks and process for making them does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Structures super conductor tracks and process for making them, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structures super conductor tracks and process for making them will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-361781