TUNNEL MAGNETO-RESISTIVE (TMR) SENSORS EMPLOYING TMR DEVICES WITH DIFFERENT MAGNETIC FIELD SENSITIVITIES FOR INCREASED DETECTION SENSITIVITY

• Main Authors: HSU, Wah Nam, KANG, Seung, Hyuk, CHEN, Wei-Chuan, LI, Xia, STEVENS-YU, Nicholas, Ka Ming
• Format: Patent
• Language: English; French; German
• Published: 05.02.2020
• Subjects: ELECTRICITY; MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; TESTING

Tunnel magneto-resistive (TMR) sensors employing TMR devices with different magnetic field sensitivities for increased detection sensitivity are disclosed. For example, a TMR sensor may be used as a biosensor to detect the presence of biological materials. In aspects disclosed herein, free layers of at least two TMR devices in a TMR sensor are fabricated to exhibit different magnetic properties from each other (e.g., MR ratio, magnetic anisotropy, coercivity) so that each TMR device will exhibit a different change in resistance to a given magnetic stray field for increased magnetic field detection sensitivity. For example, the TMR devices may be fabricated to exhibit different magnetic properties such that one TMR device exhibits a greater change in resistance in the presence of a smaller magnetic stray field, and another TMR device exhibits a greater change in resistance in the presence of a larger magnetic stray field.