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Title: Method using laser irradiation for the production of atomically clean crystalline silicon and germanium surfaces

Abstract

This invention relates to a new method for removing surface impurities from crystalline silicon or germanium articles, such as off-the-shelf p- or n-type wafers to be doped for use as junction devices. The principal contaminants on such wafers are oxygen and carbon. The new method comprises laser-irradiating the contaminated surface in a non-reactive atmosphere, using one or more of Q-switched laser pulses whose parameters are selected to effect melting of the surface without substantial vaporization thereof. In a typical application, a plurality of pulses is used to convert a surface region of an off-the-shelf silicon wafer to an automatically clean region. This can be accomplished in a system at a pressure below 10.sup.-8 Torr, using Q-switched ruby-laser pulses having an energy density in the range of from about 60 to 190 MW/cm.sup.2.

Inventors:
 [1];  [2];  [3]
  1. (Knoxville, TN)
  2. (Oak Ridge, TN)
  3. (Lenoir City, TN)
Issue Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
OSTI Identifier:
864003
Patent Number(s):
4292093
Assignee:
United States of America as represented by United States (Washington, DC) ORNL
DOE Contract Number:  
W-7405-ENG-26
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
method; laser; irradiation; production; atomically; clean; crystalline; silicon; germanium; surfaces; relates; removing; surface; impurities; articles; off-the-shelf; p-; n-type; wafers; doped; junction; devices; principal; contaminants; oxygen; carbon; comprises; laser-irradiating; contaminated; non-reactive; atmosphere; q-switched; pulses; parameters; selected; effect; melting; substantial; vaporization; typical; application; plurality; convert; region; wafer; automatically; accomplished; pressure; below; 10; -8; torr; ruby-laser; energy; density; range; 60; 190; mw; cm; laser irradiation; energy density; surface region; laser pulses; method comprises; laser pulse; silicon wafer; crystalline silicon; typical application; method comprise; surface impurities; pressure below; removing surface; moving surface; comprises laser; reactive atmosphere; atomically clean; junction device; junction devices; /134/117/136/148/219/438/

Citation Formats

Ownby, Gary W., White, Clark W., and Zehner, David M. Method using laser irradiation for the production of atomically clean crystalline silicon and germanium surfaces. United States: N. p., 1981. Web.
Ownby, Gary W., White, Clark W., & Zehner, David M. Method using laser irradiation for the production of atomically clean crystalline silicon and germanium surfaces. United States.
Ownby, Gary W., White, Clark W., and Zehner, David M. Thu . "Method using laser irradiation for the production of atomically clean crystalline silicon and germanium surfaces". United States. https://www.osti.gov/servlets/purl/864003.
@article{osti_864003,
title = {Method using laser irradiation for the production of atomically clean crystalline silicon and germanium surfaces},
author = {Ownby, Gary W. and White, Clark W. and Zehner, David M.},
abstractNote = {This invention relates to a new method for removing surface impurities from crystalline silicon or germanium articles, such as off-the-shelf p- or n-type wafers to be doped for use as junction devices. The principal contaminants on such wafers are oxygen and carbon. The new method comprises laser-irradiating the contaminated surface in a non-reactive atmosphere, using one or more of Q-switched laser pulses whose parameters are selected to effect melting of the surface without substantial vaporization thereof. In a typical application, a plurality of pulses is used to convert a surface region of an off-the-shelf silicon wafer to an automatically clean region. This can be accomplished in a system at a pressure below 10.sup.-8 Torr, using Q-switched ruby-laser pulses having an energy density in the range of from about 60 to 190 MW/cm.sup.2.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1981},
month = {1}
}

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