Semiconductor accelerometer

• US 5,251,485 A
• Filed: 05/07/1991
• Issued: 10/12/1993
• Est. Priority Date: 05/07/1990
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kondo, Yuji
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US07/695,819
• Time in Patent Office: 889 Days
• Field of Search: 73/517 B, 73/517 R, 338/2, 338/3, 338/5, 338/46, 338/43
• US Class Current: 73/514.16
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges

Abstract

A semiconductor accelerometer comprising a semiconductor base member and an acceleration response member having a semiconductor beam integrally extending from the base member and a semiconductor weight integrally formed at a tip end of the beam so as to deflect the semiconductor beam when the weight is subjected to acceleration. At least one gauge diffusion resistor is formed in the semiconductor beam. The at least one gauge diffusion resistor includes a contact diffusion region which is formed at each end of the at least one gauge diffusion resistor and which has a diffusion concentration higher than that of the at least one gauge diffusion resistor. The contact diffusion region formed at each end of the at least one gauge diffusion resistor is connected to a wiring conductor.

Claims

1. A semiconductor accelerometer comprising:

a semiconductor frame member;

a mass-spring system having a seismic mass elastically supported at its opposite sides by a plurality of beams extending from the semiconductor frame member, wherein a first pair of said beams extend from one side of the semiconductor frame member to one facing side of the seismic mass, and a second pair of the beams extend from a side of the semiconductor frame member opposite to said one side of the semiconductor frame member from which the first pair of beams extends, said second pair of beams reaching a side of the seismic mass opposite to the side to which the first pair of beams are coupled; and

a pair of gauge resistors formed in each of the beams such that one of the gauge resistors extends along a lengthwise direction of the beams and the other of the gauge resistors extends along a widthwise direction of the beams, wherein

said gauge resistors formed in the first pair of beams being interconnected to form a first Wheatstone bridge, each connection node of which is connected through a wiring conductor to a corresponding one of external connection pads formed on a first portion of the semiconductor frame member adjacent to the first pair of beams,

said gauge resistors formed in the second pair of beams being interconnected to form a second Wheatstone bridge, each connection node of which is connected through a wiring conductor to a corresponding one of external connection pads formed on a second portion of the semiconductor frame member adjacent to the second pair of beams, and

said gauge resistors having diffusion resistors and contact diffusion regions, each of said contact diffusion regions is formed at each end of the diffusion resistors and has a diffusion concentration which is higher than that of the diffusion resistors.

2. A semiconductor accelerometer claimed in claim 1 wherein each of said diffusion resistors is connected to form a series circuit in such a manner that one contact diffusion region of one end of one diffusion resistor is connected to another contact diffusion region of one end of another diffusion resistor.

3. A semiconductor accelerometer claimed in claim 2 wherein said one contact diffusion region of said one end of said one diffusion resistor is connected to said another contact diffusion region of said one end of said another diffusion resistor by the wiring conductor which has a first end connected through a contact hole to said one contact diffusion region of said one end of said one diffusion resistor and which also has a second end connected through another contact hole to said another contact diffusion region of said one end of said another diffusion resistor.