Detection piezoresistance and method for ultrathin silicon micromechanical cantilever beam under torsion mode

Abstract

The invention relates to a detection piezoresistor for an ultrathin silicon micromechanical cantilever beam under a torsional mode and a method for detecting the piezoresistor, and belongs to the technical field of micromechanical sensing. The method is specifically characterized in that the method uses shear stress distribution characteristics of the micromechanical cantilever beam under the torsional mode to penetrate a piezoresistive doped region for signal detection to the thickness of the whole silicon cantilever beam, thereby breaking through the limit that the piezoresistive sensing region of the micromechanical cantilever beam cannot overpass half of the beam thickness under the prior bending mode; and the method simultaneously combines anisotropy of silicon piezoresistive coefficient and distribution characteristic of stress tensor on the cantilever beam to optimally design the arrangement direction of the cantilever beam and the piezoresistor, so that the relative variable of the piezoresistor reaches the maximum, and the mechanical property of the cantilever beam is improved. The piezoresistor and the method have the advantages of simple structure, convenient manufacture and easy realization.

Description

Technical field [0001] The invention relates to a piezoresistance detection and a piezoresistance detection method suitable for ultra-thin silicon micromechanical cantilever beams working in a torsion mode. More precisely, the present invention uses ordinary ion doping technology to produce a sensitive piezoresistance through the thickness of the thin beam, and converts the shear stress in the torsional mode micromechanical cantilever beam into an electrical signal to detect ultra-thin silicon micro Vibration of a mechanical cantilever beam. The invention belongs to the field of micro-nano electromechanical systems. Background technique [0002] Piezoresistive silicon micro-cantilever sensors have been widely used in the fields of bioimaging technology, pressure sensitivity and biochemical trace detection in recent years due to their simple structure, easy integration, and extremely high sensitivity to force and quality. The core component of this type of sensor is the silicon ...

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Problems solved by technology

For example: M.Gel et al once proposed in the article "Sub-micron thick high sensitive piezoresistive cantileverers byboron etch stop and argon implantation" (IEEE MEMS-03, Kyoto, Japan494-497, 2003) to use argon ion implantation on the back to form front pressure Although the thinner piezoresistive sensitive element can be made in a certain depth range, the thinnest cantilever beam is only 0.4 micron; while Kenny et al. thick" (Appl.Phys.Lett.75289-291, 1999), the piezoresistive cantilever sensor with a thickness of 100 nanometers produced by epitaxial technology also has the disadvantage that the piezoresistive cannot be photolithographically formed. In addition, Due to the unavoidable thermal diffusion of ions in the subsequent thermal annealing process, the thickness of the cantilever beam is difficult to be thinner

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