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.