Browse Prior Art Database

Formation of SiO2 SiO Polycrystalline Si Structures

IP.com Disclosure Number: IPCOM000119330D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 1 page(s) / 35K

Publishing Venue

IBM

Related People

Raider, SI: AUTHOR [+2]

Abstract

A new structure, SiO2-SiO-polycrystalline Si, is disclosed. The deposited silicon monoxide, SiO, improves the electrical characteristics of SiO2-polycrystalline Si interfaces by inhibiting SiO2 decomposition.

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Formation of SiO2 SiO Polycrystalline Si Structures

      A new structure, SiO2-SiO-polycrystalline Si, is
disclosed. The deposited silicon monoxide, SiO, improves the
electrical characteristics of SiO2-polycrystalline Si interfaces by
inhibiting SiO2 decomposition.

      In an inert ambient at elevated temperatures, a reversible
reaction between crystalline Si and SiO2 occurs which decomposes SiO2
and forms a product, SiO, i.e.,
      Si + SiO2 T 2 SiO. (1)
This reaction leads to degradation of the SiO2 electrical properties.
The rate of this reaction is accelerated by mechanical damage near
the silicon surface and is significantly increased when single
crystal Si is replaced by polycrystalline Si [*].  Crystalline
Si-SiO2-polycrystalline Si structures are commonly formed as part of
present FET technology.

      To limit deterioration of the interfacial electrical properties
of these structures, a thin layer of SiO is deposited at an SiO2
surface prior to polycrystalline Si deposition and further thermal
processing.  This reduces the tendency for reaction (1) to occur.  An
interfacial SiO layer between polycrystalline Si and SiO2 thereby
reduces the extent to which interfacial electrical properties are
deteriorated.  The deposited SiO layer is not expected to degrade the
electrical properties of the structure since a suboxide layer, < 1 nm
thick, is typically present at an Si-SiO2 interface.

      Reference
(*)  K. Hofmann and S. I. Raider, "Ac...