The Optimal Design of Piezoresistive Sensor
博士 === 國立臺灣大學 === 機械工程學系研究所 === 86 === The piezoresistor has been admired for the large effect of stresses on the resistivity since 1954. Traditionally, the size of piezoresistor with regular shape has to be kept small enough to preserve the assumption of...
Main Authors: | , |
---|---|
Other Authors: | |
Format: | Others |
Language: | zh-TW |
Published: |
1998
|
Online Access: | http://ndltd.ncl.edu.tw/handle/61817995465505291904 |
id |
ndltd-TW-086NTU00490043 |
---|---|
record_format |
oai_dc |
spelling |
ndltd-TW-086NTU004900432016-06-29T04:13:50Z http://ndltd.ncl.edu.tw/handle/61817995465505291904 The Optimal Design of Piezoresistive Sensor 半導體感測器壓阻形狀之最佳化設計 Lin, Rong-Sheng 林容生 博士 國立臺灣大學 機械工程學系研究所 86 The piezoresistor has been admired for the large effect of stresses on the resistivity since 1954. Traditionally, the size of piezoresistor with regular shape has to be kept small enough to preserve the assumption of uniform stress distribution. In general, the electric potential of a piezoresistor subject to a non-uniform stress field can not be determined algebraically. Moreover, the assumption of uniform stress distribution may be questionable due to the miniaturization of transducer. The electric potential of a piezoresistor is dependent on the geometric shape, boundary conditions and stress distribution. The governing equation of electric potential with coefficients of electric conductivity and its derivatives is developed in this thesis. The electric conductivity is also formulated as an explicit form of specific resistivity, piezoresistity and temperature coefficients of resistivity. In order to investigate the electric potential numerically, a piezoresistive finite element is developed by variational scheme. Then the finite-element method can be employed to calculate the distribution of electric potential for the determination of output electrodes location. Since the distribution of impurity concentration is not uniform along the thickness of a piezoresistor as a consequence of doping method, the concept of equivalent conductivity is presented. The equivalent conductivity is expressed as an integral combination of electric conductivity developed previously. Based on the equivalent conductivity, the complex 3-dimensional analysis can be simplified to 2-dimensional analysis under the proper assumptions. The sensitivity of pressure sensors similar to Motorola X-ducer is investigated as an example. It is found that the algebraic solutions overestimate the sensitivity up to 49% under uniform low-doped concentration. The case of different impurity distributions is also studied. Finally, the method of shape optimization is applied to increase the sensitivity by fully taking the advantage of stress distribution in the available location of microsensors. The result of analysis indicated that the optimal shape of the four-terminal p-type piezoresistor would follow the maximum shear stress contour with extrusive output electrodes. Yuan-Fang Chou 周元昉 --- 1998 學位論文 ; thesis 176 zh-TW |
collection |
NDLTD |
language |
zh-TW |
format |
Others
|
sources |
NDLTD |
description |
博士 === 國立臺灣大學 === 機械工程學系研究所 === 86 === The piezoresistor has been admired for the large effect of stresses
on the resistivity since 1954. Traditionally, the size of piezoresistor
with regular shape has to be kept small enough to preserve the assumption
of uniform stress distribution. In general, the electric potential of a
piezoresistor subject to a non-uniform stress field can not be determined
algebraically. Moreover, the assumption of uniform stress distribution may
be questionable due to the miniaturization of transducer.
The electric potential of a piezoresistor is dependent on the geometric
shape, boundary conditions and stress distribution. The governing equation
of electric potential with coefficients of electric conductivity and its
derivatives is developed in this thesis. The electric conductivity is also
formulated as an explicit form of specific resistivity, piezoresistity and
temperature coefficients of resistivity. In order to investigate the electric
potential numerically, a piezoresistive finite element is developed by
variational scheme. Then the finite-element method can be employed to
calculate the distribution of electric potential for the determination of
output electrodes location. Since the distribution of impurity concentration
is not uniform along the thickness of a piezoresistor as a consequence
of doping method, the concept of equivalent conductivity is presented.
The equivalent conductivity is expressed as an integral combination of
electric conductivity developed previously. Based on the equivalent
conductivity, the complex 3-dimensional analysis can be simplified to
2-dimensional analysis under the proper assumptions.
The sensitivity of pressure sensors similar to Motorola X-ducer is
investigated as an example. It is found that the algebraic solutions
overestimate the sensitivity up to 49% under uniform low-doped concentration.
The case of different impurity distributions is also studied.
Finally, the method of shape optimization is applied to increase the
sensitivity by fully taking the advantage of stress distribution in the
available location of microsensors. The result of analysis indicated
that the optimal shape of the four-terminal p-type piezoresistor would
follow the maximum shear stress contour with extrusive output electrodes.
|
author2 |
Yuan-Fang Chou |
author_facet |
Yuan-Fang Chou Lin, Rong-Sheng 林容生 |
author |
Lin, Rong-Sheng 林容生 |
spellingShingle |
Lin, Rong-Sheng 林容生 The Optimal Design of Piezoresistive Sensor |
author_sort |
Lin, Rong-Sheng |
title |
The Optimal Design of Piezoresistive Sensor |
title_short |
The Optimal Design of Piezoresistive Sensor |
title_full |
The Optimal Design of Piezoresistive Sensor |
title_fullStr |
The Optimal Design of Piezoresistive Sensor |
title_full_unstemmed |
The Optimal Design of Piezoresistive Sensor |
title_sort |
optimal design of piezoresistive sensor |
publishDate |
1998 |
url |
http://ndltd.ncl.edu.tw/handle/61817995465505291904 |
work_keys_str_mv |
AT linrongsheng theoptimaldesignofpiezoresistivesensor AT línróngshēng theoptimaldesignofpiezoresistivesensor AT linrongsheng bàndǎotǐgǎncèqìyāzǔxíngzhuàngzhīzuìjiāhuàshèjì AT línróngshēng bàndǎotǐgǎncèqìyāzǔxíngzhuàngzhīzuìjiāhuàshèjì AT linrongsheng optimaldesignofpiezoresistivesensor AT línróngshēng optimaldesignofpiezoresistivesensor |
_version_ |
1718327899872821248 |