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Ammonolysis of Tetrakisdimethylaminosilane for Low Pressure Chemical Vapor Deposition of Silicon Nitride

IP.com Disclosure Number: IPCOM000103100D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 60K

Publishing Venue

IBM

Related People

Barbee, SG: AUTHOR [+4]

Abstract

Disclosed is an improved process for the chemical vapor deposition of carbon-free silicon nitride by addition of NH3 to Si(N(CH3)2)4 . The potential for explosion which is related to SiCl2H2 is eliminated. Attendant advantages of the disclosed procedure over existing silicon nitride deposition processes include a reduction in LPCVD silicon nitride process temperature from 800@C to 750@C, a reduction in particulate contamination yield loss, and the prevention of a film haze associated with SiCl2H2/NH3 chemistry byproduct NH4Cl formation.

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Ammonolysis of Tetrakisdimethylaminosilane for Low Pressure Chemical Vapor Deposition of Silicon Nitride

      Disclosed is an improved process for the chemical vapor
deposition of carbon-free silicon nitride by addition of NH3 to
Si(N(CH3)2)4 .  The potential for explosion which is related to
SiCl2H2 is eliminated.  Attendant advantages of the disclosed
procedure over existing silicon nitride deposition processes include
a reduction in LPCVD silicon nitride process temperature from 800@C
to 750@C, a reduction in particulate contamination yield loss, and
the prevention of a film haze associated with SiCl2H2/NH3 chemistry
byproduct NH4Cl formation.

      A high quality silicon nitride film, e.g., 45-50 A~/min., may
be deposited using dichlorosilane (SiCl2H2) and ammonia (NH3) at 0.3
torr and an average temperature of 800~C.  The accepted chemistry for
this process is:
      3 SiCl2H2+H2/N2 -   Si3N4Cl+3 HCl+6 H2

      This chemistry has several disadvantages, a key one being that
SiCl2H2, although known to be non-pyrophoric at 24~C, will detonate
in the presence of an ignition source. Additionally, the NH4Cl
byproduct (melting point at 350~C) condenses along the inlet and exit
tubing walls as a fine solid, providing a source of particulate
contamination, haze and pump oil contamination.

      The above noted disadvantages may be overcome, in particular,
the explosive hazard, by utilizing tetrakisdimethylaminosilane in
place of dichlorosilane.  T...