TITLE:
Nanosensitive Silicon Microprobes for Mechanical Detection and Measurements
AUTHORS:
Jan M Łysko, Piotr Dumania, Paweł Janus, Mirosław Grodner, Helena Kłos, Karina Skwara, Piotr Grabiec
KEYWORDS:
Force, Deflection, Probe, Mos Transistor, Inverter, Ring Oscillator, Piezoresistance
JOURNAL NAME:
Materials Sciences and Applications,
Vol.2 No.6,
June
24,
2011
ABSTRACT: Nanosensitive mechanical microprobes with CMOS transistors, inverters, inverters cascades and ring oscillators, integrated on the thin silicon cantilevers are presented. Mechanical stress shifts linear, steep switching fragment of the inverters’ electrical characteristics. Microprobes were fabricated with use of the standard CMOS technology (3.5 μm design rules, one level polysilicon gate and one level of the metal interconnections) and relief MEMS technique. Control of the silicon cantilever thickness was satisfactory in the range above the few micrometers. Several computer simulations were done to analyze and optimize transistors location on the cantilever, in respect to the mechanical stress distribution. Results of the microprobes electromechanical tests confirm high deflection sensitivity 1.2 - 1.8 mV/nm and force sensitivity 2.0 - 2.4 mV/nN, both in nano ranges. Microprobes, with the ring oscillators revealed sensitivities 5 - 8 Hz/nm. These microprobes seem to be appropriate for applications in precise chemical and biochemical sensing.