Integrated flux concentrator improves CMOS magnetotransistors

Abstract

A magnetic microsystem based on CMOS technology merged with electroplating as a post-processing step is reported. The system makes use of a lateral dualcollector magnetotransistor with suppressed-sidewallinjection (SSIMT) and a highly permeable and soft magnetic microstructure of permalloy. This structure increases the magnetic flux density in the sensitive SSIMT region. It is deposited on top of the sensor chip using a CMOS compatible electroplating technique [ 11. The system sensitivity is increased by at least one order of magnitude over the conventional SSIMT.