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Ti-Cr-Al/Cu INTERCONNECTION METALLURGY TO FABRICATE LOW AND HIGH BARRIER SCHOTTKY BARRIER DIODES IN VLSI CHIP

IP.com Disclosure Number: IPCOM000041273D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Dalal, HM: AUTHOR [+2]

Abstract

Low and high barrier Schottky barrier diodes (SBDs) are fabricated by successive layers of titanium, water-bled chromium and aluminum-copper on n-silicon (low barrier) or on platinum silicide (high barrier) substrates contacts. A clean Ti:Si interface, required to form an ideal low barrier SBD, is formed upon annealing at 400ŒC for 20 minutes in forming gas. It is pertinent that titanium be deposited in a "clean environment" where titanium is evaporated under the shutter prior to deposition on the substrates. A clean interface is rendered even if the substrates at contact holes have a layer of oxide or amorphous silicon up to a thickness of 100 ˜. The water-bled chromium is a layer of chromium containing chromium oxide, and is formed by bleeding water vapor into the deposition chamber during the chromium deposition.

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Ti-Cr-Al/Cu INTERCONNECTION METALLURGY TO FABRICATE LOW AND HIGH BARRIER SCHOTTKY BARRIER DIODES IN VLSI CHIP

Low and high barrier Schottky barrier diodes (SBDs) are fabricated by successive layers of titanium, water-bled chromium and aluminum-copper on n- silicon (low barrier) or on platinum silicide (high barrier) substrates contacts. A clean Ti:Si interface, required to form an ideal low barrier SBD, is formed upon annealing at 400OEC for 20 minutes in forming gas. It is pertinent that titanium be deposited in a "clean environment" where titanium is evaporated under the shutter prior to deposition on the substrates. A clean interface is rendered even if the substrates at contact holes have a layer of oxide or amorphous silicon up to a thickness of 100 ~. The water-bled chromium is a layer of chromium containing chromium oxide, and is formed by bleeding water vapor into the deposition chamber during the chromium deposition. The water-bled chromium layer is required as a diffusion barrier to prevent the reaction of aluminum-copper with platinum silicide and with the titanium layer. The water-bled chromium layer also prevents aluminum-copper penetration into the silicon substrate. Because titanium gathers oxygen from the water-bled chromium layer during the various heat cycles encountered in the process, a thinner layer of titanium and a thicker layer of water-bled chromium is desired to maintain barrier effectiveness. However, the high 'stress X thickness' of th...