Fabrication of industrial grade GMR multilayer magnetic sensors for non-recording applications

Abstract

Giant Magnetoresistance (GMR) technology is now becoming a popular choice in the industrial market for non-recording applications (sensor applications). In these applications, the sensor's characteristics need to be engineered for high linearity, reversibility, and high thermal stability. Among two different types of GMR technologies, such as GMR-multilayer (GMR-ML) and GMR- spin valves (GMR-SV), an attempt was made to fabricate a sensing element with high throughput based on GMR-ML due to its cost-effectiveness and relatively higher dynamic field range. Further, sensor was used as linear sensor in both omni-polar (i.e. by default) as well as bipolar (i.e. biased with permanent magnet for converting omfig ni-polar characteristics to bipolar characteristics). A detailed pilot scale fabrication of a GMR sensor with a yield of 88 % on a 4-in. wafer was presented. All the products developed using GMR-ML were evaluated in the real-time applications environment.