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 triangle T=11.9 oC. The temperature measured across the 412 μ m 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 (19.9circC increase for going from 73 μ m to 412 μ m, for the 'short' channel) while the length of the trench has a much less significant effect (3.2circC increase from 'short' to 'long' trench, for a depth of 412 μ m). 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.