Fast thermal response of silicon nanowire-heater for heat shock generation

Silicon (Si) nanowires have been widely used as sensor and heater in various fields such as biology and chemistry due to its high sensitivity and fast responsivity. In this paper, we measured the temporal response property of Si nanowire-heater through infrared microscopy. Nanowire-heaters were fabricated using silicon-on-insulator (SOI) wafer with Si heights of 15 μm and 30 μm, respectively. In order to compare the change of the temporal response property according to the structural shape, four different types of nanowire-heater were fabricated using the basic MEMS processes. To measure the transient temperature change of nanowireheaters, the voltage of square wave with constant pulse duration was applied using a function generator. According to the pulse duration, the transient temperature distribution for four different types of Si nanowire-heater was measured using infrared (IR) microscope. Consequently, regardless of the structural shape and width difference of Si nanowire-heaters, they showed a fast response time less than 1 ms when the voltage with 500 Hz pulse duration was repeatedly applied. Also, the simulated results using COMSOL multiphysics showed that they had around 100 μs response time which is around 10 times faster than the maximum time resolution of the IR microscope.