Transducer apparatus employing convoluted semiconductor diaphragms

• US 4,467,656 A
• Filed: 03/07/1983
• Issued: 08/28/1984
• Est. Priority Date: 03/07/1983
• Status: Expired due to Term

• Current Assignee: Kulite Semiconductor Products Inc
• Original Assignee: Kulite Semiconductor Products Inc
• Inventors: Kurtz, Anthony D., Mallon, Joseph R.
• Primary Examiner(s): Woodiel, Donald O.
• Application Number:
  US06/472,850
• Time in Patent Office: 540 Days
• Field of Search: 73/721, 73/727, 73/DIG. 4, 357/26, 310/800, 338/4, 338/42
• US Class Current: 73/727
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm
• CPC Class Codes: Y10S 73/04 Piezoelectric

Abstract

A pressure transducer employing a semiconductor diaphragm having a convoluted central section surrounded by a rigid peripheral section. The convolutions are a series of concentric grooves formed as squares producing a square nonplanar diaphragm in the preferred embodiment. The convolutions are formed on the semiconductor wafer by an anisotropic etch. Piezoresistive devices are diffused into the diaphragm in the peripheral region to form a bridge array. The transducer structure thus formed is capable of producing a linear and large magnitude voltage signal in response to a relatively small applied pressure or force.

Claims

1. A pressure transducer, comprising:

a convoluted semiconductor diaphragm member having a central portion manifesting a plurality of concentric recesses forming a series of convolutions and an outer nondeflecting peripheral area

at least one semiconductor sensor deposited on said diaphragm within said peripheral area with a portion of said sensor being located proximate to an edge of an outer convolution.

2. The pressure transducer according to claim 1, wherein said semiconductor diaphragm is square in configuration with said concentric recesses being a series of square shaped convolutions.

3. The pressure transducer according to claim 1, wherein said semiconductor sensor is diffused into the surface of said diaphragm.

4. The pressure transducer according to claim 1, wherein said concentric recesses each have a trapezoidal cross section.

5. The pressure transducer according to claim 1, wherein said semiconductor diaphragm is fabricated from silicon.

6. The pressure transducer according to claim 1, wherein said semiconductor sensors are piezoresistors.

7. The pressure transducer according to claim 1, wherein said convoluted recesses are formed by an anisotropic etch.

8. A pressure transducer comprising:

a convoluted semiconductor diaphragm of a relatively square shaped configuration having a central area manifesting a series of concentric square shaped convolutions with an outer nondeflecting peripheral area

first and second piezoresistive sensors deposited on said diaphragm within said peripheral area and located on opposite sides along the same first axis and operative to respond to mainly transverse stress,

third and fourth piezoresistive sensors deposited on said diaphragm within said peripheral area and located on opposite sides of a second axis, perpendicular to said first axis and operative to respond to mainly longitudinal stress.

9. The pressure transducer according to claim 8 further comprising:

interconnecting means for connecting said first, second, third and fourth piezoresistive sensors in a Wheatstone bridge array.

10. The pressure transducer according to claim 9, wherein said convolutions are formed by an anisotropic etch.