An extraordinary magnetoresistance (EMR) sensor has a planar shunt and planar leads formed on top of the sensor and extending downward into the semiconductor active region, resulting. Electrically conductive material, such as Au or AuGe, is first deposited into lithographically defined windows on top of the sensor. After liftoff of the photoresist a rapid thermal annealing process causes the conductive material to diffuse downward into the semiconductor material and make electrical contact with the active region. The outline of the sensor is defined by reactive etching or other suitable etching techniques. Insulating backfilling material such as Al-oxide is deposited to protect the EMR sensor and the edges of the active region. Chemical mechanical polishing of the structure results in a planar sensor that does not have exposed active region edges.