Vibratory transducer
First Claim
1. A vibratory transducer for vibrating a vibratory beam formed on a single silicon crystal at a natural frequency thereof and for detecting a change in the frequency of vibration of the vibratory beam dependent on change in a force applied on said single silicon crystal or environment, said transducer comprising a single silicon crystal which comprises a p-type semiconductor conductor containing impurities at a concentration of 10.sup.. or 1017 atoms/cm3 or less, and an n+ diffused layer of a single silicon crystal containing impurities at a concentration ranging from 1017 to 1018 atoms/cm3 ;
- a vibratory beam formed of the n+ diffused layer by underetching said n+ diffused layer by the selective etching technique;
said vibratory beam having at least one fixed point;
means for causing said vibratory beam to vibrate at the natural frequency; and
detecting means for detecting the vibration.
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Abstract
A vibratory transducer comprising a vibratory beam composed of an n-type layer and having at least one end fixed. The vibratory beam is formed by selectively etching an n-type layer formed by adding impurities locally to a single silicon crystal. The vibratory transducer also comprises means for vibrating the vibratory beam and means for detecting vibration of the vibratory beam. The vibratory transducer measures pressure, temperature, density, etc, by detecting change in the resonant frequency of the vibratory beam. The vibratory beam can be finely etched irrespective of the density of the impurities therein by forming the vibratory beam in an alkaline aqueous solution while applying a negative DC or pulsed voltage to a p-type layer and a positive DC or pulsed voltage to an n-type layer. The vibrating and detecting means for the vibratory beam can be easily provided by making a diode and a transistor including the vibratory beam in the transducer.
77 Citations
24 Claims
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1. A vibratory transducer for vibrating a vibratory beam formed on a single silicon crystal at a natural frequency thereof and for detecting a change in the frequency of vibration of the vibratory beam dependent on change in a force applied on said single silicon crystal or environment, said transducer comprising a single silicon crystal which comprises a p-type semiconductor conductor containing impurities at a concentration of 10.sup.. or 1017 atoms/cm3 or less, and an n+ diffused layer of a single silicon crystal containing impurities at a concentration ranging from 1017 to 1018 atoms/cm3 ;
- a vibratory beam formed of the n+ diffused layer by underetching said n+ diffused layer by the selective etching technique;
said vibratory beam having at least one fixed point;
means for causing said vibratory beam to vibrate at the natural frequency; and
detecting means for detecting the vibration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
- a vibratory beam formed of the n+ diffused layer by underetching said n+ diffused layer by the selective etching technique;
Specification