Improved piezoresistive microcantilever contact-resonance measuring system

The Institute of Semiconductor Technology LENA (Laboratory for Emerging Nanometrology) at TU Braunschweig is developing silicon-based resonantMEMS (Micro-Electro-Mechanical Systems) sensors for surface measurement technology. These sensors are based on piezoresistive, resonant silicon cantilevers with integrated measuring electronics.[13] By analyzing the shift in resonance frequency, changes can be detected and measured. The sensor signal is extracted from the measurement signal using a PLL (Phase-Locked Loop) for real-time measurements. This PLL is an electronic system comprising a signal generator, a microcontrollerbased control module, an I/Q demodulator, a piezoelectric driver with a voltage follower module, and other components. The analog circuits for each module have been developed and verified in previous work.[14] However, the system still faces deficiencies in speed, accuracy, noise, and reliability. Therefore, this work aims to improve the microcontroller-based control module. Firstly, an overvoltage protection module (OVP) should be added to the microcontroller-based control module. For this purpose, a new circuit must be designed, constructed, and tested. Finally, the new control module needs to be characterized and integrated into the existing system.