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Title: Impurity gettering in silicon using cavities formed by helium implantation and annealing

Abstract

Impurity gettering in silicon wafers is achieved by a new process consisting of helium ion implantation followed by annealing. This treatment creates cavities whose internal surfaces are highly chemically reactive due to the presence of numerous silicon dangling bonds. For two representative transition-metal impurities, copper and nickel, the binding energies at cavities were demonstrated to be larger than the binding energies in precipitates of metal silicide, which constitutes the basis of most current impurity gettering. As a result the residual concentration of such impurities after cavity gettering is smaller by several orders of magnitude than after precipitation gettering. Additionally, cavity gettering is effective regardless of the starting impurity concentration in the wafer, whereas precipitation gettering ceases when the impurity concentration reaches a characteristic solubility determined by the equilibrium phase diagram of the silicon-metal system. The strong cavity gettering was shown to induce dissolution of metal-silicide particles from the opposite side of a wafer.

Inventors:
 [1];  [1];  [1]
  1. (Albuquerque, NM)
Issue Date:
Research Org.:
AT & T CORP
OSTI Identifier:
871993
Patent Number(s):
5840590
Assignee:
Sandia Corporation (Albuquerque, NM) SNL
DOE Contract Number:  
AC04-76DP00789
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
impurity; gettering; silicon; cavities; formed; helium; implantation; annealing; wafers; achieved; process; consisting; followed; treatment; creates; internal; surfaces; highly; chemically; reactive; due; presence; numerous; dangling; bonds; representative; transition-metal; impurities; copper; nickel; binding; energies; demonstrated; larger; precipitates; metal; silicide; constitutes; basis; current; result; residual; concentration; cavity; magnitude; precipitation; additionally; effective; regardless; starting; wafer; ceases; reaches; characteristic; solubility; determined; equilibrium; phase; diagram; silicon-metal; strong; shown; induce; dissolution; metal-silicide; particles; opposite; impurity concentration; impurity gettering; internal surface; chemically react; internal surfaces; silicon wafer; silicon wafers; metal impurities; binding energies; process consisting; phase diagram; chemically reactive; cavities formed; /438/148/

Citation Formats

Myers, Jr., Samuel M., Bishop, Dawn M., and Follstaedt, David M. Impurity gettering in silicon using cavities formed by helium implantation and annealing. United States: N. p., 1998. Web.
Myers, Jr., Samuel M., Bishop, Dawn M., & Follstaedt, David M. Impurity gettering in silicon using cavities formed by helium implantation and annealing. United States.
Myers, Jr., Samuel M., Bishop, Dawn M., and Follstaedt, David M. Thu . "Impurity gettering in silicon using cavities formed by helium implantation and annealing". United States. https://www.osti.gov/servlets/purl/871993.
@article{osti_871993,
title = {Impurity gettering in silicon using cavities formed by helium implantation and annealing},
author = {Myers, Jr., Samuel M. and Bishop, Dawn M. and Follstaedt, David M.},
abstractNote = {Impurity gettering in silicon wafers is achieved by a new process consisting of helium ion implantation followed by annealing. This treatment creates cavities whose internal surfaces are highly chemically reactive due to the presence of numerous silicon dangling bonds. For two representative transition-metal impurities, copper and nickel, the binding energies at cavities were demonstrated to be larger than the binding energies in precipitates of metal silicide, which constitutes the basis of most current impurity gettering. As a result the residual concentration of such impurities after cavity gettering is smaller by several orders of magnitude than after precipitation gettering. Additionally, cavity gettering is effective regardless of the starting impurity concentration in the wafer, whereas precipitation gettering ceases when the impurity concentration reaches a characteristic solubility determined by the equilibrium phase diagram of the silicon-metal system. The strong cavity gettering was shown to induce dissolution of metal-silicide particles from the opposite side of a wafer.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {1}
}

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