| Summary: | 碩士 === 國立海洋大學 === 電子工程學系 === 82 === The objects of this paper focus on the fabrication and
characterization of high sensitive silicon pressure sensors
for measurement of gas pressure. Although the mechanic type
pressure sensors have been used widely, the silicon pressure
sensors have excellent characteristics, such as small size,
high sensitivity and the possibility of monolithic integration
of electronic devices, which may be used more attractively in
the future. In semiconductors, the numbers of charge carriers
are expected to change by applied stress, which causes the
energy gap change between the valence and conduction band.
Therefore, the resistivity would change. This is one of the
best features for silicon pressure sensors utilizing piezo-
resistance effect for measuring very low pressure. Silicon
pressure sensors consist of a thin square diaphragms an elastic
material and four piezoresistive guage resistors which are made
by diffusing impurities into the diaphragm surface. When
pressure is applied to the diaphragm, the guage resistance
will change due to the piezoresistance effect. In this
experiement, the parameters which may influence the
characteristics of sensors including the diaphragm
thickness, piezoresistors layout, dopant concentration,
junction depth and environmental temperature etc. are discussed
From the results of this experiment, it can be found that on
(100) n type Si substrate, with the diaphragm is thinner and
the junction depth is shallower, one would obtain the highest
sensitivity as the piezoresistors are along the [110] direction.
|
|---|
