INSPECTION
Figure 3) GD-OES analysis of proprietary PV film
indicates no surface charging or surface
equilibrium issues and no signal instability at the
interface region. The inconsistent film deposition
could be observed at both the near surface and
in the bulk
Table 2) Analysis of indium thin films by LA ICP-MS indicated stainless steel
contamination in the new indium film (middle column) that was traced to the
29
indium target (far right column)
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The source of this contamination was found to be standard method for elemental composition of
a new indium target shown in the far right column stainless steels and LA ICP-MS used for years in
-pv-management.com
in Figure 5. The same metallic contamination geological applications. Neither technique has
fingerprint of Cr, Fe, Ni and Mo was observed in found wide-spread applications in traditional
both the new film and this particular target. By semiconductor analysis or yield enhancement
changing out the target to a contamination-free protocols for the electronic industries, however
indium source, this problem was solved. both techniques have specific advantages over
conventional surface analyses.
In summary, GD-OES and LA ICP-MS techniques Advantages such as the collection of simultaneous
Issue V 2009
have been used in academia and in other fields for element data, and full periodic table coverage can
many years. For example, GD-OES has been the in many cases provide a faster, more cost efficient
analysis for process engineers. Depth profile
capabilities with GD-OES approach those available
with SIMS, and yet GD-OES (and LA ICP-MS)
experience no charging or surface equilibrium
issues. GD-OES and LA ICP-MS are not full
answers to all surface analysis questions, as
sensitivity can still be improved and diagnosis of
particles or determination of chemical state are
better suited for other techniques.
The advantages however outweigh the
disadvantages; GD-OES and LA ICP-MS has been
used to characterize silicon thin films as well as
those composed of CdTe, CIGS, and CdS along
Figure 4) The aging process of thin fims on glass with starting materials, sputter targets, TCO films,
substrates can be easily monitored by GD-OES front and back contacts, and glass substrates, and
depth profiling. The presence of oxygen at the are versatile analysis techniques applicable to
near surface of the “old” sample was found to be quality control, trouble shooting and yield
detrimental to PV thin film performance enhancement in the PV manufacturing process.
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