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High S/N ratio slotted step piezoresistive microcantilever designs for biosensors.

Ansari MZ, Cho C - Sensors (Basel) (2013)

Bottom Line: The cantilever step length and piezoresistor length is varied along with the operating voltage to characterise the surface stress sensitivity and thermal drifting sensitivity of the cantilevers when used as immunosensor.The numerical analysis is performed using ANSYS Multiphysics.Results show the surface stress sensitivity and the S/N ratio of the slotted step cantilevers is improved by more than 32% and 22%, respectively, over its monolithic counterparts.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Inha University, 253 Yonghyun-dong, Nam-Ku, Incheon 402-751, Korea. ansari.zahid@hotmail.com

ABSTRACT
This study proposes new microcantilever designs in slotted step configuration to improve the S/N ratio of surface stress-based sensors used in physical, chemical, biochemical and biosensor applications. The cantilevers are made of silicon dioxide with a u-shaped silicon piezoresistor in p-doped. The cantilever step length and piezoresistor length is varied along with the operating voltage to characterise the surface stress sensitivity and thermal drifting sensitivity of the cantilevers when used as immunosensor. The numerical analysis is performed using ANSYS Multiphysics. Results show the surface stress sensitivity and the S/N ratio of the slotted step cantilevers is improved by more than 32% and 22%, respectively, over its monolithic counterparts.

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The longitudinal stress distribution (MPa) in different (l, lp) piezoresistor designs for surface stress 0.04 N/m.
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f3-sensors-13-04088: The longitudinal stress distribution (MPa) in different (l, lp) piezoresistor designs for surface stress 0.04 N/m.

Mentions: The surface stress-induced longitudinal stress (σl,S) distribution in the piezoresistor elements of the slotted piezoresistive microcantilever designs in shown in Figure 3. The top edge is the fixed end of the cantilever and is fully constrained. The results for monolithic designs are also presented. The maximum stress in slotted designs is more than twice compared to the monolithic. For a given piezoresistor length, the figures show the stress magnitude is very similar in both the step lengths. In contrast, this is also evident in Figure 3 that the change in piezoresistor length has significant effect on the stress magnitude and its distribution in the cantilevers, especially in case of (100, 50) and (150, 50) designs. The maximum stress in these designs is about 35% higher. Nevertheless, the resonant frequency of these designs is also the lowest (see Table 2). Thus, in case the high frequency requirement is not critical, (100, 50) and (150, 50) are the most suitable designs to achieve high stress and therefore high resistance change in piezoresistive microcantilevers.


High S/N ratio slotted step piezoresistive microcantilever designs for biosensors.

Ansari MZ, Cho C - Sensors (Basel) (2013)

The longitudinal stress distribution (MPa) in different (l, lp) piezoresistor designs for surface stress 0.04 N/m.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3673072&req=5

f3-sensors-13-04088: The longitudinal stress distribution (MPa) in different (l, lp) piezoresistor designs for surface stress 0.04 N/m.
Mentions: The surface stress-induced longitudinal stress (σl,S) distribution in the piezoresistor elements of the slotted piezoresistive microcantilever designs in shown in Figure 3. The top edge is the fixed end of the cantilever and is fully constrained. The results for monolithic designs are also presented. The maximum stress in slotted designs is more than twice compared to the monolithic. For a given piezoresistor length, the figures show the stress magnitude is very similar in both the step lengths. In contrast, this is also evident in Figure 3 that the change in piezoresistor length has significant effect on the stress magnitude and its distribution in the cantilevers, especially in case of (100, 50) and (150, 50) designs. The maximum stress in these designs is about 35% higher. Nevertheless, the resonant frequency of these designs is also the lowest (see Table 2). Thus, in case the high frequency requirement is not critical, (100, 50) and (150, 50) are the most suitable designs to achieve high stress and therefore high resistance change in piezoresistive microcantilevers.

Bottom Line: The cantilever step length and piezoresistor length is varied along with the operating voltage to characterise the surface stress sensitivity and thermal drifting sensitivity of the cantilevers when used as immunosensor.The numerical analysis is performed using ANSYS Multiphysics.Results show the surface stress sensitivity and the S/N ratio of the slotted step cantilevers is improved by more than 32% and 22%, respectively, over its monolithic counterparts.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Inha University, 253 Yonghyun-dong, Nam-Ku, Incheon 402-751, Korea. ansari.zahid@hotmail.com

ABSTRACT
This study proposes new microcantilever designs in slotted step configuration to improve the S/N ratio of surface stress-based sensors used in physical, chemical, biochemical and biosensor applications. The cantilevers are made of silicon dioxide with a u-shaped silicon piezoresistor in p-doped. The cantilever step length and piezoresistor length is varied along with the operating voltage to characterise the surface stress sensitivity and thermal drifting sensitivity of the cantilevers when used as immunosensor. The numerical analysis is performed using ANSYS Multiphysics. Results show the surface stress sensitivity and the S/N ratio of the slotted step cantilevers is improved by more than 32% and 22%, respectively, over its monolithic counterparts.

Show MeSH