Microscale temperature sensing using novel reliable silicon vertical microprobe array: Computation and experiment

Microscale temperature sensing using a fabricated novel vertical silicon microprobe array was investigated for the first time using a combined simulation and experimental technique. In this context, silicon microprobes were designed with 3 μm in diameter and 30 μm in height. These high-aspect-ratio probes are found to be effective in microscale multisite temperature sensing. The designed microprobes (p-type) were fabricated in < 111 > out-of-plane orientation using vapor-liquid-solid (VLS) technique on n-type silicon substrate. The temperature dependent shift in the rectifying current-voltage (I-V) curves of the embedded p-n diode was experimentally determined and the temperature sensitivity of diode was found to be − 2.3 mV/K at 0.1 μA. A complete 3-D model of the microprobe was created and finite element (FE) method was applied to compute the sensing capability by capturing temperature distribution taking anisotropic and phonon scattering effects on thermal conductivity of silicon into account. The obtained computational result on microscale temperature sensitivity has shown a similar trend of experimental findings. FE simulation thus can serve as a tool to a-priori predict temperature sensing capabilities of microprobes used in many applications such as artificial electronic fingertips of robotic hand/prosthetics, biological soft samples.