Browse Prior Art Database

Buried Metal Silicide Conductors in (100) Silicon

IP.com Disclosure Number: IPCOM000121072D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 4 page(s) / 772K

Publishing Venue

IBM

Related People

Akbar, S: AUTHOR [+5]

Abstract

This article describes a process to form a thin, highly conducting, cobalt disilicide monocrystalline patterned layer at an arbitrary depth in (100) silicon crystal lattice.

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Buried Metal Silicide Conductors in (100) Silicon

      This article describes a process to form a thin, highly
conducting, cobalt disilicide monocrystalline patterned layer at an
arbitrary depth in (100) silicon crystal lattice.

      The cobalt disilicide was formed by a 200 keV, 2.0E17 cm-2 ion
implantation of Co-59+ ions into 470oC heated (100) silicon substrate
held at a 45-degree implant angle such that the cobalt ions
penetrated deeper in the (110) direction into the silicon.
Subsequent 900oC annealing in hydrogen formed a 75 nm thin,
epitaxial, continuous, highly conducting cobalt disilicide layer with
a resistivity of 24E-6 ohm-cm, at a depth of 70 nm from the silicon
surface.

      To extend the silicon crystal lattice on top of the silicide,
depending upon the intended use, two techniques were employed:  an
ultra-high vacuum chemical vapor deposition low temperature epitaxial
deposition at 600oC for a conductor close to the silicon surface or a
high temperature epitaxy 900oC process for conductors buried several
microns deep in the silicon.

      The cross-sectional high resolution TEM of the low temperature
epitaxy process, shown in Fig. 1, delineates an abrupt silicon/cobalt
disilicide interface.  The sharp metallurgical junction is confirmed
by the SIMS profile depicted in Fig. 2.  The conducting silicide is
buried about 200 nm from the silicon surface.  The high temperature
epitaxy process also yields abrupt interfaces, as shown in Fig....