US 12,313,479 B1
Semiconductor strain gage
Franklin Curtis Wong, Simi Valley, CA (US); Robert Andrew Mueller, Simi Valley, CA (US); Kimberly Lakea Harrison, Martinez, CA (US); Farzad Khademolhosseini, Burlingame, CA (US); and Carolyn D. Bianco, San Francisco, CA (US)
Assigned to Piezo-Metrics Inc, Simi Valley, CA (US)
Filed by Piezo-Metrics Inc, Simi Valley, CA (US)
Filed on Jan. 10, 2024, as Appl. No. 18/408,964.
Application 18/408,964 is a division of application No. 17/700,266, filed on Mar. 21, 2022, granted, now 11,906,375.
Claims priority of provisional application 63/164,923, filed on Mar. 23, 2021.
Int. Cl. G01L 1/22 (2006.01); G01L 1/20 (2006.01)
CPC G01L 1/2293 (2013.01) [G01L 1/205 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A semiconductor strain gage comprising:
at least one strain gage, each strain gage of the at least one strain gage having a body, where in the body includes a first width, a first thickness, a first length, and a longitudinal axis along a first direction, the body further comprising a first portion of a device layer of a semiconductor-on-insulator substrate, and wherein the device layer comprises a first semiconductor having a first resistivity;
a first contact and a second contact each including a doped region of the device layer and a bond pad disposed on and electrically connected with the doped region, wherein the doped region comprises the first semiconductor and a first dopant and wherein the doped region has a second resistivity that is lower than the first resistivity, and wherein the first and second contacts are separated by a first distance along the longitudinal axis; and
a frame that includes a second portion of the device layer;
wherein the at least one strain gage is coupled to the frame by at least one sprue that extends between the frame and the body of the at least one strain gage;
wherein the at least one strain gage has a damage threshold, and wherein each of the at least one sprue includes a stress-concentration feature, the stress-concentration feature being configured to break in response to a first force that is less than the damage threshold; and
wherein the at least one strain gage has a gage resistance, and wherein the gage resistance is based on the first resistivity, the first thickness, the first width, and the first distance along the longitudinal axis of the body.