Size-Reduced Two-Dimensional Integrated Magnetic Sensor Fabricated in 0.18-μm CMOS Process

Two-dimensional integrated magnetic sensors have been investigated in order to reduce their size for use in a magnetic self-levitation motor. The two-dimensional integrated magnetic sensor investigated in this paper is composed of a 16 x 16 array of Hall sensors and fabricated by a 0.18-m complementary metal-oxide-semiconductor (CMOS) standard process. The sizes of the Hall elements are 1 x 1, 2 x 2, 3 x 3, and 6 x 6 m(2). Hall element of dimension 1 x 1 m(2)was the minimum size in the fabrication process rule. The dimension of one pixel in which the Hall element was embedded was 20 x 20 m(2). The average sensitivity of the arrayed Hall sensors at four sizes was about 0.140 mV/mT with a DC magnetic field. The product sensitivity at four sizes of Hall sensors was about 0.089 mV/(mAmT), which is better than that of our previous work. Degradation of the product sensitivity was not seen in reduced-size Hall elements. These results reveal that a Hall element of size 1 x 1 m(2) has enough sensitivity for sensing the impeller position of a magnetically suspended motor. (c) 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.