This paper reports two novel sensing modes for the 3axis Hall-effect sensor based on an inverted pyramid structure. The proposed current-spinning schemes enable 3-axis magnetic field measurements with reduced readout complexity (6 less switching phases for 3D1) while preserving sensitivity and offset. Residual offsets in the millitesla range at 1 V supply voltage were measured on three identical samples using 6 - or 12 -phase current spinning sequences, with in-plane voltage and currentrelated sensitivities up to 16.7 mV/ V/ T and 86.1 V/ A/ T, respectively. These modes represent a more efficient and simpler readout method for the pyramid sensor, while remaining competitive with the state-of-the-art.

Microelectronic magnetic sensors are essential in diverse applications, including automotive, industrial, and consumer electronics. Hall-effect devices hold the largest share of the magnetic sensor market, and they are particularly valued for their reliability, low cost and CMOS compatibility. This paper introduces a novel 3-axis Hall-effect sensor element based on an inverted pyramid structure, realized by leveraging MEMS micromachining and CMOS processing. The devices are manufactured by etching the pyramid openings with TMAH and implanting the sloped walls with n-dopants to define the active area. Through the use of various bias-sense detection modes, the device is able to detect both in-plane and out-of-plane magnetic fields within a single compact structure. In addition, the offset can be significantly reduced by one to three orders of magnitude by employing the current-spinning method. The device presented in this work demonstrated high in-plane and out-of-plane current- and voltage-related sensitivities ranging between 64.1 to 198 V A⁻¹ T⁻¹ and 14.8 to 21.4 mV V⁻¹ T⁻¹, with crosstalk below 4.7%. The sensor exhibits a thermal noise floor which corresponds to approximately 0.5μT/Hz at 1.31 V supply. This novel Hall-effect sensor represents a promising and simpler alternative to existing state-of-the-art 3-axis magnetic sensors, offering a viable solution for precise and reliable magnetic field sensing in various applications such as position feedback and power monitoring. (Figure presented.)