Selective ion source

Patent · Mon Jan 01 00:00:00 EST 1996

OSTI ID:870418

Leung, Ka-Ngo ^[1]

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1. Hercules, CA

A ion source is described wherein selected ions maybe extracted to the exclusion of unwanted ion species of higher ionization potential. Also described is a method of producing selected ions from a compound, such as P.sup.+ from PH.sub.3. The invention comprises a plasma chamber, an electron source, a means for introducing a gas to be ionized by electrons from the electron source, means for limiting electron energy from the electron source to a value between the ionization energy of the selected ion species and the greater ionization energy of an unwanted ion specie, and means for extracting the target ion specie from the plasma chamber. In one embodiment, the electrons are generated in a plasma cathode chamber immediately adjacent to the plasma chamber. A small extractor draws the electrons from the plasma cathode chamber into the relatively positive plasma chamber. The energy of the electrons extracted in this manner is easily controlled. The invention is particularly useful for doping silicon with P.sup.+, AS.sup.+, and B.sup.+ without the problematic presence of hydrogen, helium, water, or carbon oxide ions. Doped silicon is important for manufacture of semiconductors and semiconductor devices.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• DOE Contract Number: AC03-76SF00098
• Assignee: Regents, University of California (Oakland, CA)
• Patent Number(s): US 5517084
• OSTI ID: 870418
• Country of Publication: United States
• Language: English

Related Subjects

selective
source
described
selected
extracted
exclusion
unwanted
species
ionization
potential
method
producing
compound
ph
comprises
plasma
chamber
electron
means
introducing
gas
ionized
electrons
limiting
energy
value
specie
extracting
target
embodiment
generated
cathode
immediately
adjacent
extractor
draws
relatively
positive
manner
easily
controlled
particularly
useful
doping
silicon
problematic
presence
hydrogen
helium
water
carbon
oxide
doped
manufacture
semiconductors
semiconductor
devices
electron energy
electron source
particularly useful
semiconductor device
semiconductor devices
doped silicon
plasma chamber
immediately adjacent
producing selected
easily controlled
ionization energy
ionization potential
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