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Browse Prior Art Database

Ion Implanted Schottky Barrier Diodes

IP.com Disclosure Number: IPCOM000087123D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Brack, K: AUTHOR [+3]

Abstract

The electrical characteristics of practical Schottky barrier diodes (SBDs) are greatly influenced by the properties of the metal silicon interface and by the edge limiting the Schottky contact. It is difficult to prevent the growth of a minute intervening oxide layer and surface contamination before metal deposition. Apart from this, the deposited interface of aluminum silicon diodes, for example, is altered during the low-temperature annealing step by the formation of spikes or by solid-to-solid epitaxial deposition of silicon, depending upon the silicon content of the aluminum. As a result of curvature-dependent field enhancement and oxide charge, the electrical behavior along the edge of an "unguarded" device is, at best, poorly defined.

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Ion Implanted Schottky Barrier Diodes

The electrical characteristics of practical Schottky barrier diodes (SBDs) are greatly influenced by the properties of the metal silicon interface and by the edge limiting the Schottky contact. It is difficult to prevent the growth of a minute intervening oxide layer and surface contamination before metal deposition. Apart from this, the deposited interface of aluminum silicon diodes, for example, is altered during the low-temperature annealing step by the formation of spikes or by solid-to-solid epitaxial deposition of silicon, depending upon the silicon content of the aluminum. As a result of curvature-dependent field enhancement and oxide charge, the electrical behavior along the edge of an "unguarded" device is, at best, poorly defined.

Instead of implementing the aluminum silicon junction by evaporation, low- energy, high-dose aluminum implantation is used, so that the active metal semiconductor interface is placed underneath the original silicon surface. The implanted area is then contacted by conventional Al deposition. The resulting structure is shown in the drawing. Al+ layer 1 is implanted into the surface of an n type epitaxial layer 2 grown on an n type Si-substrate 3. Al+ layer 1 is defined by a masking SiO(2) layer 4 and contacted by conventional Al deposition 5. Backside contact 6 is applied over an n+ layer 7.

The implanted, buried aluminum layer makes for an ultra-clean metal semiconductor contact. The concen...