Measuring and testing – Fluid pressure gauge – Diaphragm
Patent
1990-03-26
1992-12-01
Woodiel, Donald O.
Measuring and testing
Fluid pressure gauge
Diaphragm
73706, 73708, 73721, 338 3, 338 4, G01L 708, G01L 906
Patent
active
051671581
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a semiconductor film pressure sensor based on the piezo resistance effect of a semiconductor film pattern, and a method of manufacturing the semiconductor film pressure sensor.
BACKGROUND ART
Recently, attention has been paid to a semiconductor pressure sensor utilizing the piezo resistance effect of semiconductor such as silicon and germanium.
For instance, the inventors have proposed a film pressure sensor which is formed with an n-type microcrystalline silicon (.mu.c-Si) formed by a plasma CVD method as a pressure-sensitive resistance layer (Japanese Patent Application No. 111377/1986).
In the film pressure sensor, not only the adhesion between the diaphragm and the gauge section, but also the adhesion between the insulating layer and the pressure-sensitive resistance layer is satisfactory; however, the pressure-sensitive resistance layer is still unsatisfactory in temperature characteristic.
In addition, a structure using a p-type polycrystal silicon as its pressure-sensitive resistance layer has been proposed ("Sensor Technique", December 1985, Vol. 5, No. 13, pp. 30-34).
In formation of a p-type polycrystalline silicon layer by the plasma CVD method, it is necessary to use high power, because if high frequency power (RF power) less than 100 W is used, then it will become amorphous. In the case also where the gas ratio is changed, it is necessary to employ high power. However, it is well known in the art that plasma uniformity is, in general, low with high power.
Accordingly, in the case where a film pressure sensor is formed with the p-type polycrystalline silicon layer as the photo-sensitive resistance layer, the photo-sensitive resistance layer is improved in temperature characteristic; however, it is not uniform in resistance. Therefore, the film pressure sensor thus formed is disadvantageous in that in formation of a bridge circuit, it is necessary to perform resistance compensation which is rather troublesome.
DISCLOSURE OF THE INVENTION
In view of the foregoing, the present invention provides a semiconductor film pressure sensor using an n-type polycrystalline silicon layer to form pressure-sensitive resistance layers (films).
That is, the inventors have found it through experiments that, in a semiconductor film pressure sensor, the use of an n-type polycrystalline silicon layer to form pressure-sensitive resistance layers is superior in manufacturing efficiency and in sensitivity characteristic to the use of a p-type polycrystalline silicon layer. The invention has been developed on this finding.
Furthermore, the inventors have performed intensive research on the n-type polycrystalline silicon layer which has been considered difficult to use as pressure-sensitive resistance layer. As a result, it has been found that pressure-sensitive resistance layers uniform and excellent in characteristic can be obtained by greatly increasing the temperature condition in the plasma CVD method which is heretofore 180.degree. to 300.degree. C. The present invention is developed according to this finding. In the invention, the substrate temperature is set to 500.degree. to 650.degree. to form an n-type polycrystalline silicon layer which is used to provide pressure-sensitive resistance layers.
In the invention, in manufacturing a film pressure sensor, coarsely adjusting patterns and finely adjusting patterns for zero point adjustment are formed using the same material as the pressure-sensitive resistance layers. After the sensor has been formed, coarse adjustment is carried out by selectively using the coarsely adjusting patterns, and then fine adjustment is performed by selectively using the finely adjusting patterns.
Preferably those zero point adjusting patterns are L-shaped or U-shaped so as to increase the substantial line width.
According to the method using the coarsely adjusting patterns and the finely adjusting patterns, a fine adjusting pitch can be provided in a limited region, so that the resistances can be readily adjusted with high accuracy. And th
REFERENCES:
patent: 3858150 (1974-12-01), Gurtler et al.
patent: 4003127 (1977-01-01), Jaffe et al.
patent: 4657775 (1987-04-01), Shioiri et al.
patent: 4670969 (1987-06-01), Yamada et al.
patent: 4771639 (1988-09-01), Saigusa et al.
Transducers '85, International Conference on Solid-State Sensors and Actuators, pp. 430-433, NY, US-"Polysilicon layers lead to a new generation of pressure sensors".
Inagaki Hiroshi
Kamachi Makoto
Suzuki Noritake
Tabata Aki
Tajika Jun
Kabushiki Kaisha Komatsu Seisakusho
Woodiel Donald O.
LandOfFree
Semiconductor film pressure sensor and method of manufacturing s does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor film pressure sensor and method of manufacturing s, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor film pressure sensor and method of manufacturing s will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-497261