Boron diffusion in polycrystalline Si-on-single crystal Si systems has been studied by secondary ion mass spectrometry. The extrapolated B-diffusion profiles in polycrystalline Si and in the single crystal Si substrate reveal a discontinuity at the polycrystalline Si-single crystal Si interface. The discontinuity in the B profiles is believed to occur due to the blockage of B-defect complexes by the interfacial oxide between polycrystalline Si and the single-crystal Si substrate, as well as the immobility of these defect complexes in single crystal Si. The B in the implant peak region above the B solid solubility limit is found to be immobile in single crystal Si during annealing due to the formation of electrically inactive B-defect complexes. In polycrystalline Si, however, our results show that the B in the peak region spreads out more rapidly than in single crystal Si possibly due to the diffusion of B-defect complexes along grain boundaries. The B-defect complexes are electrically inactive as determined by spreading resistance analysis. If the B concentration is lowered below the solid solubility limit, either by decreasing the dose or by raising the anneal temperature, no discontinuity is observed in the B profile across the polycrystalline Si-single crystal Si interface.
The fabrication and principal characteristics of an electrically calibrated absolute radiometer are described. The receiver substrate incorporates an evaporated chromium-nickel thermopile, an electrical shield, a copper thermal diffuser disk, an evaporated chromium electrical heating element, and a goldblack absorber. All insulating layers are evaporated silicon monoxide; the thermopile and heater are made by a photoetching process. The performances of several radiometers are discussed. For example, a 28-junction version has a responsivity and NEP of 93 mV/W and 50 nW, respectively, in air, with a time constant of 15 sec and a surface responsivity uniform to better than 1%. The radiometers require only a few corrections of small magnitude. An analysis of sources of error and residual uncertainties shows that the over-all precision of this type of radiometer is at least 0.5% for a power level of 50 microW. Comparative radiometric measurements are described that support this claim.
Record keeping within research animal care facilities is a key part of the guidelines set forth by national regulatory bodies and mandated by federal laws. Research facilities must maintain records of animal health issues, procedures and usage. Facilities are also required to maintain records regarding regular husbandry such as general animal checks, feeding and watering. The level of record keeping has the potential to generate excessive amounts of paper which must be retained in a fashion as to be accessible. In addition it is preferable not to retain within administrative areas any paper records which may have been in contact with animal rooms. Here, we present a flexible, simple and inexpensive process for the generation and storage of electronic animal husbandry records using smartphone technology over a WiFi or cellular network.
Articles you may be interested inThe effect of preamorphization energy on ultrashallow junction formation following ultrahigh-temperature annealing of ion-implanted silicon This paper discusses the diffusion of As, P, and B in amorphous and polycrystalline silicon-onsingle-crystal silicon systems during rapid thermal annealing and furnace annealing. It is found that the changes of microstructure during annealing play a major role in determining the diffusion profiles in the substrate as well as in the polycrystalline silicon layer. For As or P doping, a drive-in diffusion results in a much larger grain microstructure for as-deposited amorphous silicon than for as-deposited polycrystalline silicon, which leads to the formation of shallower junctions in the substrate for the first case. For B doping, there is little difference in the fmal microstructure and junction depth between the two cases. At high anneal temperatures, the native interfacial oxide breaks up, causing epitaxial realignment of the polycrystalline silicon film and subsequent enhanced diffusion in the substrate.1397
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