New Generation of Crystal Quartz Thin-Film Multijunction Thermal Converters
The design of a new generation of planar multijunction thermal converters (PMJTCs) on quartz membranes and on quartz crystal chips improves the frequency response of the PMJTC in the frequency range from 100 kHz to 100 MHz and allows a decrease in the uncertainties. For a heater resistance of 1 kOmega ac-dc voltage transfer differences smaller than 5 muV/V are calculated for frequencies above 100 kHz up to 1 MHz. This is a reduction of more than one order of magnitude in the ac-dc voltage transfer differences for such high heater resistance in comparison to the PMJTCs with Si3N4/SiO2/Si3N4 sandwich membrane on a silicon chip. The quartz PMJTCs allow the improvement of the standard uncertainties to 3 muV/V in the frequency range of 100-500 kHz and 5 muV/V for 700 kHz to 1 MHz. The model for calculating the ac-dc voltage transfer differences and the uncertainty budget are given
Design and Fabrication of MJTCs on Quartz Substrates at NIST
Wet and dry etching is employed in the fabrication of new planar thin-film multijunction thermal converters (MJTCs) on quartz membranes and crystalline quartz chips at the National Institute of Standards and Technology (NIST). The use of crystalline quartz as a material for the membrane and chip improves the performance of the MJTC in the frequency range of 100 kHz-100 MHz. Simulations of the ac-dc voltage transfer difference for a heater resistance of 400 Omega in the frequency range of 1-100 MHz show a reduction in the ac-dc transfer difference of more than one order of magnitude, in comparison with the MJTCs fabricated on silicon chips. The devices that have been fabricated, although not optimized for 100 MHz, have been shown to have reasonable performance for their 20-V maximum input.
Prevalence of Headache Within a College Student Population: A Preliminary Analysis
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