Microheater isolation characterisation to aid the optimisation of a MEMS Leidenfrost engine

This paper reports on the implementation of test structures to characterize the design of a microheater that facilitates localized heating to power a Leidenfrost micro-engines. The test structures are designed to characterize the effect on heat transfer of trenches etched into the silicon substrate. With no trench, the temperature difference is ΔT = 11.9 °C. The temperature measured across the 412 µm deep "long" trench was 43.6 °C while it was 40.4 °C for the "short" trench. The results show that increasing the depth of the trench increases the temperature difference across the trench (19.9 °C increase for going from 73 µm to 412 µm, for the "short" channel) while the length of the trench has a much less significant effect (3.2 °C increase from "short" to "long" trench, for a depth of 412 µm). The test structure measurements agreed well with simulation results confirming the validity of using computer aided design as an integral part in the development of microheater designs.