Neutron Transmutation Doping of Silicon Slices
A process for irradiating float zone crystal in slice form to reduce irradiation charges is described. Results indicate that breakage losses are a maximum of 8% and may be as low as 3%. In this process, wherein ingot identity is maintained, targeting precision and resistivity uniformity are equivalent to rod doped NTD crystals. Lifetime measured on 6mm slugs handled along with the slices are significantly lower than those observed on rods, but a 100 µ second minimum specification is still possible at resistivities above 25 ohm cm. Cosmetic stains on as-cut slices were observed, but techniques for avoiding them were devised. A qualitative cost comparison of the two doping methods is made.
KeywordsMinority Carrier Lifetime Reactor Facility Undoped Crystal Neutron Transmutation Doping Silicon Slice
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