Semiconductor device

Abstract

The invention relates to a semiconductor device. A Hall element is provided with: a magnetism sensing unit (20) which is configured from a second conductivity-type impurity diffusion layer provided ona first conductivity-type semiconductor substrate (10), and which has four ends in plan view; and four electrodes (31) to (34). The surface of the magnetic sensing part is composed of a second conductivity type impurity diffusion layer which is arranged at each of four end parts and is higher in concentration than the magnetic sensing part. The impurity diffusion layer, which is a magnetic sensing part, has a first depth (D1) from the surface of the semiconductor substrate. The semiconductor device has a first concentration gradient (S1) in which the impurity concentration of the second conductivity type increases in the depth direction from the surface of the semiconductor substrate to a second depth (D2) shallower than the first depth. And a second impurity gradient (S2) in which the impurity concentration of the second conductivity type decreases in the depth direction from the second depth to the first depth, the second depth being less than or equal to half of the first depth, and the first concentration gradient being steeper than the second concentration gradient.

Description

technical field [0001] The present invention relates to a semiconductor device, and more particularly, to a semiconductor device having a Hall element. Background technique [0002] The Hall element is used in various applications because it can perform non-contact position sensing or angle sensing as a magnetic sensor. [0003] With a real Hall element, an output voltage is produced even when no magnetic field is applied. The voltage output when the magnetic field is zero is referred to as an offset voltage. The cause of the offset voltage is considered to be an imbalance in potential distribution inside the element due to mechanical stress applied to the element from the outside, alignment deviation during manufacturing, or the like. When a Hall element is used as a magnetic sensor, it is necessary to remove such an offset voltage. [0004] In order to remove (eliminate) the offset voltage, the spinning current method is generally used. [0005] Hall elements can be i...

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Problems solved by technology

[0017] However, in the method of Patent Document 2, a plurality of depletion layer control electrodes must be used, and a complicated control circuit is required, so there is a difficulty in that the chip size increases and the cost increases.

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