APPLICATIONS OF AMS TO ELECTRONIC AND SILVER-HALIDE IMAGING RESEARCH

A collaborative program is underway between the University of Rochester's Nuclear Structure Research Laboratory (NSRL) and the Eastman Kodak Company to apply AMS to the detection of trace elements in silver halides and in silicon semiconductor devices. In the manufacture of both it is important to understand the role played by dopants and impurities under various processing conditions. For example, in silicon semiconductor sensors, an important impurity is chlorine which arises from various sources including the borophosphosilicate glass (BPSG) applied on the surface as an insulator. The combination of neutron activation (NA) of the silicon wafers which converts stable chlorine-35 to a radioactive isotope, chlorine-36, and the subsequent depth profiling of this rare isotope using the accelerator mass spectrometry (AMS) facility at the NSRL, permits a quantitative measurement to be made of the depth distribution of chlorine in the wafers with a present sensitivity comparable to the very best achieved by secondary ion mass spectrometry (SIMS). The current NA/AMS sensitivity can be improved by longer neutron irradiation. An important advantage of NA followed by AMS is that it provides an unambiguous result at ppb levels since the problem of contamination during measurement, which is a major concern for a common element like Cl, is eliminated. In the field of silver halide imaging, platinum group elements (PGE) are often added as dopants. AMS has been demonstrated to have a very high sensitivity to the quantitative detection of such elements in bulk material and may also be useful in depth profiling these elements in single-crystal silver halides to aid in the understanding of structure-property relationships. The University of Rochester presently has the only facility capable of making these measurements in the United States.