Browse Prior Art Database

Self Aligned Ion Implanted Oxidation Barrier For Semiconductor Devices

IP.com Disclosure Number: IPCOM000048541D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Hansen, HH: AUTHOR [+2]

Abstract

In this method for forming contacts and other structures for semiconductor devices an oxidation barrier layer, silicon nitride, is formed by direct ion implantation of an element, nitrogen, into a silicon substrate. Various horizontal and vertical contact surfaces are formed by ion implantation of nitrogen either vertically or at an angle with respect to a recess formed in the surface of the substrate.

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Self Aligned Ion Implanted Oxidation Barrier For Semiconductor Devices

In this method for forming contacts and other structures for semiconductor devices an oxidation barrier layer, silicon nitride, is formed by direct ion implantation of an element, nitrogen, into a silicon substrate. Various horizontal and vertical contact surfaces are formed by ion implantation of nitrogen either vertically or at an angle with respect to a recess formed in the surface of the substrate.

Fig. 1 represents a partially fabricated semiconductor device for example, a bipolar transistor, including subcollector layer 10 and epitaxial layer 12 grown on silicon semiconductor substrate 14. Also shown is a silicon dioxide filled isolation trench 16 and a surface passivation layer 18. In the present process, vertical trench 20 is anisotropically etched to the desired depth, preferably by a dry etching process, to expose a surface to which a buried contact is required.

After forming trench 20, nitrogen ions are implanted directly into the exposed surface of layer 10 at the bottom of trench 20. The nitrogen combines with the silicon of layer 10 to form silicon nitride layer 22 (Fig. 2). Next a thermal oxidation process is used to grow a thin layer of silicon dioxide 24 on the non- implanted side-walls of trench 20.

Nitride layer 22 is selectively removed by etching, and trench 20 is then filled by deposited N-type silicon and etched back to form an epitaxial plug 26 which acts as a reach-through contact to epitaxial layer 10. Oxid...