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Browse Prior Art Database

Using Titanium Nitride and Silicon Nitride for VLSI Contacts

IP.com Disclosure Number: IPCOM000053200D
Original Publication Date: 1981-Sep-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Ting, CY: AUTHOR

Abstract

This article describes the use of titanium nitride (TiN) and silicon nitride (Si(3)N(4)) for very large-scale integration (VLSI) circuit contacts.

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Using Titanium Nitride and Silicon Nitride for VLSI Contacts

This article describes the use of titanium nitride (TiN) and silicon nitride (Si(3)N(4)) for very large-scale integration (VLSI) circuit contacts.

When using titanium (Ti) as contact metallurgy in integrated circuits, it not only maintains a very low contact sheet resistivity to n-type contacts, but it also provides a good diffusion barrier between Al and Si. However, when Ti is totally reacted with Al, it loses its barrier behavior. For 1000 angstroms Ti, the reaction between Ti and Al limits the annealing temperature to 450 degrees C for 30 to 60 minutes, and not to 500 degrees C.

This article describes a novel technique for using TiN inside contact holes as contact material and forming Si(3)N(4) at the periphery of the contacts. It is well known that TiN is a good barrier with low electrical resistivity that allows devices to be annealed at 500 degrees C or higher without junction degradation, while the Si(3)N(4) is used to prevent any possible Al penetration through the peripheral and pin-hole areas where TiN may not cover. The TiN is formed at contacts by first annealing Ti at 500 degrees C in nitrogen ambient for 30 to 60 minutes to saturate Ti with nitrogen without TiSi(2) formation. A second high temperature annealing cycle should follow at one of the following conditions for 30 to 60 minutes. a) In N(2) at ~/~ 1200 degrees C b) In NH(3) at ~/~ 950 degrees C c) In NH(3) plasma at ~/~ 800 degrees...