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Simple Method for Making Thin Crystalline Nb films

IP.com Disclosure Number: IPCOM000088335D
Original Publication Date: 1977-May-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Alessandrini, EI: AUTHOR

Abstract

An important consideration in preparing thin films of Nb is ease of preparation, particularly where such metallurgy is to be used in the fabrication of Josephson tunneling devices. This article provides a simple method for making thin crystalline Nb films which utilizes an exploding wire technique.

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Simple Method for Making Thin Crystalline Nb films

An important consideration in preparing thin films of Nb is ease of preparation, particularly where such metallurgy is to be used in the fabrication of Josephson tunneling devices. This article provides a simple method for making thin crystalline Nb films which utilizes an exploding wire technique.

In a vacuum system evacuated to the order of 10/-6/ torr, a filament made by braiding two 20 mil, 1-inch long Nb wires together can be exploded as follows: A DC current of 28 amps is applied to the braided filament, causing the wires to be heated to incandescence. A (100) oriented Si substrate is placed two inches away from the Nb source at room temperature and is shuttered for two minutes during the outgassing of the Nb wire. After two minutes, the shutter is removed so that the silicon substrate is directly under the glowing wires. After an additional three minutes at 28 amps, the current through the wires is increased to thirty amps, and the wires explode instantaneously, depositing a thin film of Nb on the silicon substrate.

Using reflection electron defraction and electron microprobe techniques, it was determined that the structure of the resulting films is polycrystalline, randomly oriented and, at least, 40 Angstroms in thickness. In order to prepare thicker films, the time the Nb braid is held at incandescence can be increased.

The above-described deposition technique is advantageous, since films can be prepare...