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Silicon Dopant Delineation by Irradiation of Transmission Electron Microscopy Cross Sections

IP.com Disclosure Number: IPCOM000122331D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 47K

Publishing Venue

IBM

Related People

Cunningham, B: AUTHOR [+3]

Abstract

Electron beam irradiation of silicon is known to produce defects in silicon. The amount of damage is dependent on differences in dopant concentration n the silicon and the total energy of the irradiation. We have used this phenomenon to develop a novel technique to delineate semiconductor junctions in silicon.

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Silicon Dopant Delineation by Irradiation of Transmission Electron
Microscopy Cross Sections

      Electron beam irradiation of silicon is known to produce
defects in silicon.  The amount of damage is dependent on differences
in dopant concentration n the silicon and the total energy of the
irradiation.  We have used this phenomenon to develop a novel
technique to delineate semiconductor junctions in silicon.

      Techniques such as chemically etching of SEM (Scanning Electron
Microscope) or TEM (Transmission Electron Microscope) cross sections
are not reliable for junction delineation due to variables such as
etch rate, effects stress, and wet etch chemistry.  Secondary Ion
Mass Spectroscopy (SIMS) can be used to determine vertical profiles,
but it is difficult to obtain lateral diffusion information.  The
electron irradiation technique eliminates the problems of chemical
etching while providing information on both vertical and lateral
diffusions (Figure 1).

      The technique consists of irradiating a cross-sectional TEM
specimen with high energy (400 keV) electrons.  A high density of
defects is produced at the junction due to the strain produced by
differences in dopant concentration.  The cross section is ion milled
to remove the surface damage, leaving a clear delineation of the
junctions.

      Disclosed anonymously.