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METHOD OF MINIMIZING Al-Si ALLOYING IN SEMICONDUCTOR DEVICES

IP.com Disclosure Number: IPCOM000038947D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Campbell, D: AUTHOR [+7]

Abstract

Disclosed is a method to minimize Al penetration in semiconductor devices which otherwise leads to yield loss due to emitter-base and Schottky barrier diode (SBD) leakage. Per this method, the Al-Cu in the contacts is oxidized to form an Al2O3 passivation layer. In conventional processing, a gap is formed around device contact (Image Omitted) windows in barrier metallurgy as a consequence of nitride hole formation and subsequent undercut from glass etchants. The structure of the device is indicated in Fig. 1A which shows the underlying Si 1, a PtSi layer 2 covered by a Cr/Cr2O3 layer 3 which also covers the Si3N4 layer 4. The SiO2 in the device is indicated by 5. The barrier gap 6 may provide a channel by which the Al-Cu metallurgy 7 may make contact with the underlying PtSi or the silicon substrate.

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METHOD OF MINIMIZING Al-Si ALLOYING IN SEMICONDUCTOR DEVICES

Disclosed is a method to minimize Al penetration in semiconductor devices which otherwise leads to yield loss due to emitter-base and Schottky barrier diode (SBD) leakage. Per this method, the Al-Cu in the contacts is oxidized to form an Al2O3 passivation layer. In conventional processing, a gap is formed around device contact

(Image Omitted)

windows in barrier metallurgy as a consequence of nitride hole formation and subsequent undercut from glass etchants. The structure of the device is indicated in Fig. 1A which shows the underlying Si 1, a PtSi layer 2 covered by a Cr/Cr2O3 layer 3 which also covers the Si3N4 layer 4. The SiO2 in the device is indicated by 5. The barrier gap 6 may provide a channel by which the Al-Cu metallurgy 7 may make contact with the underlying PtSi or the silicon substrate. Such Al penetration, or alloying, results in devices which are leaky or shorted and has a major impact on device yields of SBDs and transistors. The foregoing effect may be minimized or eliminated by oxidizing the Al-Cu within the cavity to form an Al2O3 passivation layer 8 (Fig. 1B). There are several ways to effect the oxidation and passivation steps. The vapor oxidant, which may be H2O, O2, N2O, CO or CO2 among others, is introduced during the initial deposition of 200- 500 Ao Al-Cu by continuous H2O bleeding to achieve the structure in Fig. 1B. The vapor oxidant may also be introduced in the process aft...