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 DT = 11.9 degC. The temperature measured across the 412 um deep 'long' trench was 43.6 degC while it was 40.4 degC for the 'short' trench. The results show that increasing the depth of the trench increases the temperature difference across the trench (19.9 degC increase for going from 73 um to 412 um, for the 'short' channel) while the length of the trench has a much less significant effect (3.2 degC increase from 'short' to 'long' trench, for a depth of 412 um). 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.