Asahi Kasei Emd Corporation

Sentron Ag

Katsumi Kakuta

Takashi Yoshida

Masaru Suzuki

Christian Schott

Makoto Kataoka

Yo Yamagata

Yuichi Kanayama

Takayuki Namai

The present invention relates to a magnetic sensor with which magnetic characteristics are made extremely stable by consideration of an area of contact of a base layer of a magnetic substance and a semiconductor substrate. On a semiconductor substrate () a plurality of Hall elements () are embedded so as to be coplanar to a top surface of the semiconductor substrate while being mutually spaced apart by a predetermined distance, and above the Hall elements and the semiconductor substrate, a base layer (), having coefficient of thermal expansion differing from that of the Hall elements and partially covers a region of each Hall elements, is formed via a protective layer (), and a magnetic flux concentrator (), having an area larger than the base layer and with magnetic amplification, is formed on the base layer. An area of contact of the base layer of the magnetic substance and the semiconductor substrate is made small to lessen the generation of an offset voltage.

Magnetic sensor and method of manufacturing thereof

A Hall element is provided which has a high sensitivity and contributes to an improvement in S/N ratio per current by using a low-concentration n-well within a suitable range. The Hall element includes a p-type semiconductor substrate layer of p-type silicon, and an n-type impurity region located in a surface of the p-type semiconductor substrate layer, the n-type impurity region functioning as a magnetic sensing part. A p-type impurity region is located in a surface of the n-type impurity region, and n-type regions are located laterally of the p-type impurity region. A p-type substrate region having a resistivity equal to that of the p-type semiconductor substrate layer is located to extend around the n-type impurity region. An impurity concentration N in the n-type impurity region functioning as the magnetic sensing part is preferably from 1&#xd7;10to 3&#xd7;10(atoms/cm) and a distribution depth of the impurity concentration is preferably from 3.0 &#x3bc;m to 5.0 &#x3bc;m.

Hall element and magnetic sensor

The present invention relates to a position detecting device capable of canceling an error due to looseness in a vertical direction and of eliminating variation in temperature characteristics by calculating a ratio between output voltages of a plurality of Hall elements. Assuming that the Hall voltage Vheof a Hall element becomes A&#xb7;K&#xb7;Bhe(A is the amplification factor of a preamplifier, K is a constant, and Bheis the magnetic flux density the Hall element receives), then a PI regulator automatically adjusts the bias point of the PI output by feedback control in such a manner that A&#xb7;K&#xb7;BheVref=AGND (=0) holds. The Hall voltage Vheof the Hall element after amplification becomes A&#xb7;K&#xb7;Bhe. Since K=&#x2212;Vref/A&#xb7;Bhe, the Hall voltage Vheof the Hall element is given by &#x2212;Vref&#xb7;Bhe/Bhe

Position detecting device and position detecting method

An angle detection apparatus for detecting an angle of a rotatable magnetic field source comprises first and second magnetic sensor units for detecting first and second magnetic components of the magnetic field of the magnetic field source, driving means for driving the first and second magnetic sensor unit and control means. The control means control an output signal of the first magnetic sensor unit so as to have a fixed value and the driving means drive the second magnetic sensor unit according to the same drive conditions as those applied to the first magnetic sensor unit at the time when the first magnetic sensor unit is controlled by said control means so that an output signal of the second magnetic sensor unit is proportional to the tangent of said angle.

Growing community of inventors

Tokyo, Japan

Katsumi Kakuta