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Method to Generate Ultra-Thin, Uniform Silicon-on-Insulator Films for Microelectronic Applications

IP.com Disclosure Number: IPCOM000112344D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Kesan, VP: AUTHOR [+2]

Abstract

It has been difficult to generate uniform, ultra-thin (< 500 &angstrom.) SOI with good reproducibility. We propose a method of generating these ultra-thin SOI films by growing large-grain polysilicon on top of a patterned oxide wafer where the patterned wafer serves as a template to nucleate large grain size polysilicon overlayers.

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Method to Generate Ultra-Thin, Uniform Silicon-on-Insulator Films
for Microelectronic Applications

      It has been difficult to generate uniform, ultra-thin (<  500
&angstrom.) SOI with good reproducibility.  We propose a method  of
generating these ultra-thin SOI films by growing large-grain
polysilicon on top of a patterned oxide wafer where the patterned
wafer serves as a template to nucleate large grain size polysilicon
overlayers.

      It is necessary to generate thin Si layers on top of an
insulating layer in order to make silicon-on-insulator (SOI) wafers
for deep sub-micron CMOS technology.  The Si overlayers have to be
less than 500 &angstrom.  thick and very uniform (+-5%) in order to
maintain threshold voltage control between devices on 8 inch silicon
wafers.  While several techniques, viable in principle, have been
proposed for SOI for thicknesses up to about 60 nm, it is clear that
going to SOI thicknesses of say 30 nm by those techniques would be
very difficult.  Thicknesses less than 50nm would be needed for
0.1&mu.m CMOS technology and future CMOS generations.

      Proposed is a method to reproducibly generate very thin Si
overlayers and generate a SOI structure useful for various
microelectronic applications.  The method involves the deposition of
polycrystalline silicon on (a) a patterned oxide substrate, or (b) a
oxide/nitride matrix substrate or (c) a matrix of any two dissimilar
materials (Figure).  Preferential nucleation of...