In this study, a ZnO nanorods (NRs) patterned MEMS piezoresistive silicon micro-cantilever was fabricated as environmental monitor. The fabrication starts from bulk silicon, utilizing photolithography, diffusion, inductively coupled plasma (ICP) cryogenic dry etching, Zinc DC-sputtering, and chemical bath deposition (CBD) etc. This sensor shows a humidity sensitivity value of 6.35 ± 0.27 ppm/RH% at 25 °C in the range from 30% RH to 80% RH.

A developed transferable micro force sensor was evaluated by comparing its response with an industrially manufactured device. In order to pre-identify sensor properties, three-dimensional (3-D) sensor models were simulated with a vertically applied force up to 1000 µN. Then, controllable batch fabrication was performed by alternately utilizing inductively coupled plasma (ICP) reactive ion etching (RIE) and photolithography. The assessments of sensor performance were based on sensor linearity, stiffness and sensitivity. Analysis of the device properties revealed that combination of a modest stiffness value (i.e., (8.19 ± 0.07) N m⁻¹) and high sensitivity (i.e., (15.34 ± 0.14) V N⁻¹) at different probing position can be realized using a meander-spring configuration. Furthermore, lower noise voltage is obtained using a double-layer silicon on insulator (DL-SOI) as basic material to ensure high reliability and an excellent performance of the sensor.

Silicon and germanium pillar structures (i.e., micro- and nanowires) were fabricated by a top-down approach including nanoimprint lithography and cryogenic dry etching. Various etching parameters were tested to ensure a reliable fabrication process. The impression of nanomechanical properties of such 3-D structures were extracted experimentally by nanoindentation showing promising and comparative results to utilize such nanostructures as small force artefacts.

A piezo resistive, phase locked loop (PLL) controlled micro tactile measurement system for contact resonance spectroscopy (CRS) at high-aspect-ratio geometries was developed and characterised. Therefore, a piezo resistive silicon cantilever with a silicon tip at its free end was brought into contact with a sample surface and excited into resonance by a piezo actuator. The resonance frequency of the contacted cantilever was tracked by a homemade closed-loop PLL circuit. Different materials and layer thicknesses of photo resist (PR) on silicon were used to validate the system. To optimise the sensitivity and efficiency of the measurement system, amplitude and phase of the cantilever in surface contact were analysed under different contact forces and excitation amplitudes.