Silicon microcantilevers with MOSFET detection

Abstract

We report the fabrication of silicon microcantilevers with MOSFET detection, to be used in force measurements for biomolecular detection. Thin cantilevers are required for a high force sensitivity. Therefore the source and drain of the transistors have been

Piezoresistive cantilevers for nanomechanical sensing

“…When CMOS integration is not intended, it is preferable to use crystalline silicon, which has a much higher piezoresistive coefficient than polysilicon. So the same group later presented cantilevers with a similar structure fabricated in crystalline silicon on SOI substrates, with either piezoresistive detection [64] or MOSFET detection [127]. For cantilevers with 250 lm length, 2 lm leg width (total width 8 lm) and a thickness of 465 nm on the piezoresistor and 325 nm elsewhere, they achieved a force sensitivity of 158 lV/nN, a noise of 5.9 lV (1 Hz-1 kHz) and a minimum detectable force of 37 pN with a relative standard deviation of 8% over 24 devices [49].…”

Self sensing cantilevers for the measurement of (biomolecular) forces

“…The complete process consists of 6 photolithographic steps on the component side and one on the backside for the DRIE of the silicon and the etching of the BOX (Buried OXide). The complete description can be found in [4,5]. In Fig.…”

“…We have recently fabricated crystalline silicon cantilevers, integrating N-doped piezoresistors [4] or n-MOSFET transistors [5] using Arsenic in order to obtain a small PN-junction depth and orienting the cantilevers on the non-standard (100) direction on the wafer surface to maximize the piezoresistive coefficient [6].…”

Biomolecule recognition using piezoresistive nanomechanical force probes

“…Such a device would reveal itself very versatile and could be applied also in a new type of very high sensitive biosensors able to detect even a single molecule, becoming thus important in ultrasensitive detection of biomedical markers for early stage disease diagnosis. Embedding an electrical read-out into the cantilever, such as a resistor 10,11 or a metaloxide-semiconductor field effect transistor (MOSFET), 12,13 exploiting the piezoresistive effect of silicon, 14,15 can serve to this purpose. In this system, the deflection is measured directly by the resistance variation.…”