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Browse Prior Art Database

Method for Avoiding Hillocks in Tunneling Junctions

IP.com Disclosure Number: IPCOM000089814D
Original Publication Date: 1977-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Matthews, JW: AUTHOR

Abstract

Thermal cycling of thin-film oxide, low temperature, junction tunneling devices sometimes results in the appearance of shorts across a junction. Some of these electrical shorts are believed to result from the formation of hillocks which rupture an oxide barrier. This article describes a method for avoiding hillocks in the junction region. The method consists of ensuring that the junction covers a single grain.

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Method for Avoiding Hillocks in Tunneling Junctions

Thermal cycling of thin-film oxide, low temperature, junction tunneling devices sometimes results in the appearance of shorts across a junction. Some of these electrical shorts are believed to result from the formation of hillocks which rupture an oxide barrier. This article describes a method for avoiding hillocks in the junction region. The method consists of ensuring that the junction covers a single grain.

The technique used to produce an unusually large grain in a narrow stripe 10 of a lead alloy is illustrated in Fig. 1. The technique consists of making a stripe 10 in which there is a bulge 11. If a grain boundary 12 is found during the growth of a bulge 11, like that in Fig. 1, the surface tension in the boundary 12 will cause it to move so as to reduce its surface area. Thus, a boundary like that in Fig. 2 will move to give the configuration in Fig. 3.

Once a single large grain has been formed, it is oxidized to form the barrier, and another similar large grain 40 is grown on top of it, as illustrated in Fig. 4. The upper layer 40 is shown hatched.

Although the boundary-free region in the stripes has been shown as circular in Figs. 1-4, other shapes may be more effective. One possible example 51 is shown in Fig. 5. Another, perhaps better, shape 61 is shown in Fig. 6.

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