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 beater resistance of 1 k Omega ac-dc voltage transfer differences smaller than 5 mu V/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 mu V/V in the frequency range of 100-500 kHz and 5 mu V/V for 700 kHz to I MHz. The model for calculating the ac-dc voltage transfer differences and the uncertainty budget are given.