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Growth of Patterned Epitaxial Calcium Silicide On Silicon

IP.com Disclosure Number: IPCOM000120960D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 49K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+3]

Abstract

The growth of epitaxial metallic films on top of semiconductor substrates holds enormous potential for VLSI applications. These metal films are used as interconnects in semiconductor circuits. The patterning of these films is, therefore, crucial for their use. Calcium Silicide (CaSi2) is one such material and is grown on top of silicon. For the growth of CaSi2, one of the first steps is that the silicon surface is heated to 1000~C in ultrahigh vacuum. This high temperature does not allow the use of "usual" methods of patterning involving organic resists. The use of metal masks restricts the minimum line width in addition to introducing contamination in the process.

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Growth of Patterned Epitaxial Calcium Silicide On Silicon

      The growth of epitaxial metallic films on top of semiconductor
substrates holds enormous potential for VLSI applications.  These
metal films are used as interconnects in semiconductor circuits.  The
patterning of these films is, therefore, crucial for their use.
Calcium Silicide (CaSi2) is one such material and is grown on top of
silicon. For the growth of CaSi2, one of the first steps is that the
silicon surface is heated to 1000~C in ultrahigh vacuum. This high
temperature does not allow the use of "usual" methods of patterning
involving organic resists.  The use of metal masks restricts the
minimum line width in addition to introducing contamination in the
process.

      Disclosed is a method that allows for patterning at this
elevated temperature.  Calcium silicide can be grown epitaxially on
(111) Silicon utilizing the following technique.  Thermally oxidized
(111) Silicon is patterned using lithographic tools, i.e., optical,
electron beam, or X-rays, to expose an organic photoresist stencil.
This organic stencil then serves as a mask to allow etching of the
thermal oxide down to the silicon surface.  The stencil is removed
leaving a patterned oxide mask on top of the silicon substrate.  This
oxide mask has the capability of withstanding temperatures of 1000~C.
Calcium is then blanket deposited onto the patterned oxide/silicon
substrate.  This is followed by a thermal anneal between 200~ a...