Device and method for on-chip mechanical stress sensing

US10352792B2 · kind B2 · utility

Assignee

• TEXAS INSTRUMENTS INCORPORATED · US

Inventors

• Umidjon Nurmetov · Munich, DE
• Ralf Brederlow · Poing, DE
• Baher Haroun · Allen, US

Key dates

• Filing date: Jul 14, 2017
• Grant date: Jul 16, 2019
• Expiry date: Jul 14, 2037

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D84/209
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An integrated circuit (IC) chip includes a substrate of a piezo-electric material having a first resistivity coefficient associated with a first direction that is longitudinal to a first crystal axis and a second resistivity coefficient associated with a second direction that is transverse to the first crystal axis. The first and second resistivity coefficients have opposite signs. The IC chip also includes a first stress sensing element formed in the substrate and coupled to pass a first current therethrough. The first stress sensing element includes a first resistor aligned such that the major direction of current flow through the first resistor is in the first direction and a second resistor coupled in series with the first resistor and aligned such that the major direction of current flow through the second resistor is in the second direction. A ratio of the resistance of the second resistor to the resistance of the first resistor is equal to a value α, where α is equal to the ratio of the first resistivity coefficient to the second resistivity coefficient.