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Contact Metallization for Schottky Barrier Diodes

IP.com Disclosure Number: IPCOM000046052D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Campbell, DR: AUTHOR [+3]

Abstract

In this Schottky barrier diode structure, a transition metal silicide is provided as a barrier against aluminum penetration.

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Contact Metallization for Schottky Barrier Diodes

In this Schottky barrier diode structure, a transition metal silicide is provided as a barrier against aluminum penetration.

The Schottky barrier diode structure 10 formed on silicon body 12 with an overlying layer 14 of Si0/2/ has a platinum silicide layer 16 in contact with body 12, an overlying transitional metal silicide, preferably tantalum silicide 18, overlying layer 16, and a metallurgy stripe 20. Among the various silicides, co-sputtered TaSi/2/ is the optimum choice. It can be deposited quite readily and reproducibly by co-sputtering, with the added benefit that in-situ sputter cleaning of the contact can be performed, if needed.

The Si/Ta ratio can be selected to optimize properties, such as stress and resistivity. It is very adherent to oxide, nitride, silicon and polysilicon. Its barrier height of .60 V allows it to form ohmic contacts with both N+ and P+ silicon, and low barrier Schottky diodes with N and P type Si. It is an excellent barrier against aluminum penetration at temperatures 550OEC and is relatively inert and corrosion resistant. It is amorphous as-deposited and, provided its crystallization temperature (approximately 400OEC) is not exceeded, has no grain boundaries to act as sites of enhanced Al penetration, thus improving its barrier properties over polycrystalline films, such as TiW.

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