Orthogonal fluxgate type magnetic microsensors with wide linear operation range

摘要: This thesis presents a study on the development of microfabricated fluxgate type magnetic sensors operating within wide linear operation range. Fluxgate are powerful devices due to their high sensitivity, low offset, and temperature stability. Unfortunately, range is limited, since an attempt increase also increases power dissipation sensor for traditionally used parallel configuration. In this study, with developed use orthogonal configuration closed magnetization path excitation. scope work, three different microsensor structures suitable developed, fabricated, characterized. The named as: rod macro sensor, micro ring sensor. All have CMOS compatible fabrication process flow. Furthermore, fabricated by using only standard thin film deposition photolithography techniques, enabling batch these structures. planar sensing coils electroplated FeNi core. Apart from design electroplating intensively investigated directly affects performance sensors. uses 20 µm diameter gold bonding wire as excitation rod, 10 thick core over wire. AC current passing through creates periodical field in radial direction, which always perpendicular external be detected along With idea increasing without structure verified. By 200 mA-peak sinusoidal at 100 kHz, resistance ±2.5 mT reached 0.5 mm long core, whereas ±250 µT 4 modified version can wafer level techniques. For formed layer copper sandwiched between two layers forming ferromagnetic cross-sectional dimensions 8 × 2 µm, 16 respectively. operates having 0.5, 1, cores 1100, 410, 160 µT, independent conditions peaks larger than mA, required saturate frequencies lower where skin effect not dominant. perming, equivalent noise density, 102.8 µV/mT, 7.1 268 nT/√Hz @ 1 Hz, mW, respectively given conditions. analysis showed that decreasing dimensions. has composed cascaded rings single step, control properties passes middle sewing thread, providing circular loop. angle changes according position ring, leads partially mode. tests maximum frequency extended MHz level, thinner layer. A 180 sensitivity 730 µV/mT 4-ring structure, 22 38 inner outer radius, comparison previously reported state art show first realized accomplishment work. compatible, system metallization producing coils, fabricating wafers post process.