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Silicon Doping Sources for Low Pressure Molecular Chemical Vapor Deposition

IP.com Disclosure Number: IPCOM000122691D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Kuech, TF: AUTHOR [+2]

Abstract

Described is a method in obtaining high doping efficiency and mass transport limited doping characteristics in low pressure molecular chemical vapor deposition (MOCVD) growth, as used in the fabrication of semiconductor devices.

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This is the abbreviated version, containing approximately 84% of the total text.

Silicon Doping Sources for Low Pressure Molecular Chemical Vapor
Deposition

      Described is a method in obtaining high doping efficiency
and mass transport limited doping characteristics in low pressure
molecular chemical vapor deposition (MOCVD) growth, as used in the
fabrication of semiconductor devices.

      Typically, the doping efficiency of all used silicon gas
sources deteriorates and becomes temperature activated at low
pressures or short residence times in the reactor. The figure shows a
graph of Si2H6 doping with reactor pressure and how electron
concentration varies with the influence of growth temperature.  At
high pressures, Si2H6 is mass transport limited in its doping
behavior but becomes temperature activated at low pressures.  A mass
transport limited behavior is desirable due to the greater doping
uniformity achieved.

      Calculations indicate that doping by Si2H6 do not proceed by
the unimolecular decomposition of Si2H6 but rather by the reaction of
Si2H6 with AsH3 at low temperatures. Both Si2H3PHSi3 and Si2H5PH2 are
known compounds which are stable at room temperature and their As
analogs certainly exist.  Si2H5AsH2 and Si3H3AsH2 are probably formed
in the gas phase from the direct reaction of Si2H6 and AsH3 .  It is
these compounds which may be the species responsible for the great
doping efficiency of Si2H6 at high pressures.  The temperature
dependence of Si2H6 at low reactor pressures and short residence
times is related to...