Series in MICROSYSTEMS

edited by P. A. Besse,
M. Gijs,
R. S. Popovic,
Ph. Renaud

Vol. 17:

Enrico Schurig,
Highly Sensitive
Vertical Hall Sensors
in CMOS Technology
.
2005, 214 p., 64,00. ISBN 3-86628-023-8

This book describes the principles how to obtain in CMOS technology highly sensitive Hall sensors that can measure surface-parallel magnetic field components, the so-called vertical Hall sensors (VHS). It gives theoretical and practical guidelines for the VHS design in order to achieve sensitivities as high as SI =400 V/(AT) and SV=0.04V/(VT) without any modification of the CMOS process. A new innovative design for VHS is presented using six sensor contacts instead of the traditional ones using four or five. The developed Hall devices have been successfully integrated into electronic circuitry for signal treatment. The book also presents a systematic study of the sensor offset and the compensation methods, in particular the so-called spinning-current method. Using these techniques the VHS can obtain residual offset values as low as 200m T for a bias voltage of about 2V. Based on the developed Hall sensor, two completely integrated microsystems are presented. The first one for 2-axial magnetic field measurements demonstrates the feasibility of a contactless angular encoder with a precision better than 0.8 without any special calibration in the temperature range of 30C to 100C. The second one is the first fully CMOS integrated single-chip 3D Hall probe.

Enrico Schurig, was born in Elsterwerda, Germany, in 1972. He obtained his Ms. Sc. degree in Physics from the Martin-Luther University of Halle, Germany in 1996 with a specialization in solid-state physics. In 1998 he has joined the Institute of Microelectronics and Microsystems at the Swiss Federal Institute of Technology in Lausanne (EPFL) as a research and teaching assistant., with a special interest in the long-term stability of silicon sensors. In 2004 he obtained his Ph.D. for his work in the field of CMOS-compatible vertical Hall sensors.

Keywords: Hall sensors, CMOS technology, integrated magnetic sensors.

Series in MICROSYSTEMS

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