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In-Situ N-Doped Polysilicon Emitter Process with Precise Control of Interfacial Oxygen within Same Tool

IP.com Disclosure Number: IPCOM000104427D
Original Publication Date: 1993-Apr-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 89K

Publishing Venue

IBM

Related People

Agnello, PD: AUTHOR [+2]

Abstract

Disclosed is a method whereby an ultra-clean (oxygen and water vapor free) atmospheric pressure Si deposition system is used to I) introduce controlled amounts of oxygen at the Si interface and followed in the same tool by II) the deposition of in situ N-doped Si at high concentrations for the emitter.

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This is the abbreviated version, containing approximately 52% of the total text.

In-Situ N-Doped Polysilicon Emitter Process with Precise Control of Interfacial Oxygen within Same Tool

      Disclosed is a method whereby an ultra-clean (oxygen and water
vapor free) atmospheric pressure Si deposition system is used to I)
introduce controlled amounts of oxygen at the Si interface and
followed in the same tool by II) the deposition of in situ N-doped Si
at high concentrations for the emitter.

      To implement this invention it is proposed that an ultra-clean
atmospheric pressure deposition system with measured and controlled
input of dilute oxygen be used for (I) controlled oxygen dosing of
the interface.  The figure shows that it is possible to expose the Si
surface to small concentrations of oxygen in a hydrogen carrier for
periods of 10 minutes at temperatures in the range 650-750ºC to
yield interfacial oxygen concentrations in the range of <>1-3 times
10 sup 15 cm sup -2.  Variation of time, concentration and
temperature outside the range of the figure would be expected to
yield a wider range of interfacial oxygen concentrations.  (When
operated without added oxygen the ultra-clean system is capable of
forming Si interfaces with <<>10 sup 12 cm sup -2 oxygen atoms.  In
addition is has been shown that changing the carrier gas to argon (or
presumably another inert gas) leads to a much faster oxidation of the
interface.  The use of hydrogen or mixtures of hydrogen and an inert
gas allow the controlled dosing of oxygen at the interface to be
obtained in a convenient time.  The use of hydrogen is helpful in
slowing down the oxidation so that small background concentrations of
oxygen in a deposition system will not lead to rapid, uncontrolled
oxidation and to too high oxygen concentrations at the interface.

      The second part (II) of the invention consists of following the
oxygen dosing of the interface in the same atmospheric pressure tool
with a deposition of N-doped Si for the emitter.  It has been
discovered that in the ultra-clean atmospheric pressure syste...