Browse Prior Art Database

High Conductivity Multiphase Metal-Silicide Alloy

IP.com Disclosure Number: IPCOM000040660D
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Joshi, RV: AUTHOR

Abstract

A technique is described whereby the conductivity of silicide structures, as used in the metal oxide silicon (MOS) semiconductors, is enhanced through the use of an alloyed salicide process. Through the use of selective thin metal deposition and annealing techniques, the resistivity of the silicides is lowered. Also, an improvement in the thermal stability and oxidation resistance of the metals or silicides used to form the semiconductor is attained. Silicides of refractory metals, such as titanium, cobalt and nickel, are used in submicron MOSFET salicide technology due to their low resistivities. However, silicides, such as cobalt and nickel, present thermal stability and bridging problems. The concept described herein provides a process to improve the thermal stability and reduce bridging problems.

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High Conductivity Multiphase Metal-Silicide Alloy

A technique is described whereby the conductivity of silicide structures, as used in the metal oxide silicon (MOS) semiconductors, is enhanced through the use of an alloyed salicide process. Through the use of selective thin metal deposition and annealing techniques, the resistivity of the silicides is lowered. Also, an improvement in the thermal stability and oxidation resistance of the metals or silicides used to form the semiconductor is attained. Silicides of refractory metals, such as titanium, cobalt and nickel, are used in submicron MOSFET salicide technology due to their low resistivities. However, silicides, such as cobalt and nickel, present thermal stability and bridging problems. The concept described herein provides a process to improve the thermal stability and reduce bridging problems. The process involves the deposition of a thin metal layer of super- alloy, such as Ni, Co, Ti, Pt and other commonly-used silicides in salicide processing, as shown in Fig. 1. Metal silicide is formed by reacting the metal over selective areas of silicon. The remaining unreacted metal is removed by a wet chemical etch without affecting the newly formed disilicide or the surrounding oxide. Low resistivity refractory metals, such as W or Mo or a low resistivity and high temperature metal - Rh, other than the metals used for formation of silicide, but having the solubility in the metal silicide are deposited selectively on the metal silicide at 400-500oC through selective chemical vapor deposition techniques. Upon annealing at high temperatures, the super-alloy di...