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Producing Contacts for Integrated Semiconductor Devices

IP.com Disclosure Number: IPCOM000085510D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Bohg, A: AUTHOR [+4]

Abstract

The ohmic and Schottky barrier diode (SBD) contacts are applied to the Si surface by a mask. Semiconductor technologies for high-integration densities use a double layer, for example, Si(3)N(4) on SiO(2), as a mask material determining the geometry of the contact.

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Producing Contacts for Integrated Semiconductor Devices

The ohmic and Schottky barrier diode (SBD) contacts are applied to the Si surface by a mask. Semiconductor technologies for high-integration densities use a double layer, for example, Si(3)N(4) on SiO(2), as a mask material determining the geometry of the contact.

During the etching of the contact hole (Fig. 1A), a window 1, etched into the Si(3)N(4) layer, serves as an etching mask for etching the SiO(2) layer. This step leads to an overhang 2 of the Si(3)N(4)layer, so that after vapor deposition of contact material 3 a cavity 1 is formed and the contact material does not cover the full Si contact surface 5.

The metal subsequently vapor deposited on contact metal 3 to form metallic supply line system 6 (Fig. 1B) may:
a) Establish a direct contact (spike) 7

to the Si, which would lead to a spurious

electrical parallel connection of an SBD

with different electrical characteristics. And;
b) React with the Si, thus impairing the reverse

voltage characteristics of an SBD. The formation

of a spike is also problematical for emitter

contacts.

Impurities 8 which may become lodged under the overhang 2 reduce the breakdown characteristics of an SBD.

As shown in Figs. 2A and 2B, these problems are eliminated by contact material 3, rather than being vapor deposited, being applied by electroless plating, i.e., by chemical deposition (Fig. 2A). A lateral contact (spike) of metallic supply line system 6 (Fig. 2B), to be su...