JPS5842281A - Hall element - Google Patents

Abstract

PURPOSE:To increase the magnetic sensitivity of the titled element by a method wherein sheet resistance is increased at both side face sections of the substrate, on which Hall output electrodes will be provided, and the sheet resistance is reduced in the center part of the substrate. CONSTITUTION:Current input electrodes 1 and 2 are provided at both end parts of the semiconductor substrate 11, and the Hall output electrodes 31 and 32 are provided at both side face parts of the substrate. The sheet resistance of the substrate 11 is increased at both side face sections and reduced in the center part. As a result, the short-circuit efficiency between the current input electrodes 1 and 2 and the Hall output electrodes 31 and 32 can be reduced, and high magnetic sensitivity can be obtained. As regards the substrate 11, one which is thin at both side face sections, thick in the center part, the impurity density is low at both side face part, and high in the center part can be used. Also, the interval between two current input electrodes can be formed wider at both side face sections and narrower in the center part.

Description

[Detailed Description of the Invention] The present invention provides magnetic sensation! l! This invention relates to a Hall element having current input electrodes at both ends with improved performance.

A Hall element is often used as an element that is sensitive to magnetism, but the structure of a conventional Hall element is a rectangular piece of material that exhibits the Hall effect with a uniform film thickness and uniform conductivity, as shown in Figure 1. Current input electrodes 1.2 are attached to both ends of a semiconductor piece 10 (hereinafter referred to as a semiconductor piece since a semiconductor is mainly used as this material), and hole output electrodes 31,452t- are attached to both sides of this semiconductor piece 100. It consists of a set configuration. When a current is passed through the Hall element from the current input electrode 1.2 and an i-field B is applied perpendicularly to the semiconductor surface, a lateral Lorentz force acts on the carriers flowing through the semiconductor.
Since the carrier is biased toward the '- side, a Hall electric field is generated inside, and nine-hole output electrodes 31 are provided on both sides. ! A Hall voltage vm is applied between 12 and 12. In the conventional element shown in FIG. 1, under a constant voltage applied to the current input electrodes 1 and 2K and a constant magnetic field of the semiconductor piece 10K and
The Hall voltage VH (i.e., the magnetic sensitivity of the Hall element 8N>) is shown in relation to the ratio W/1-(the ratio of the width W between the Hall output electrodes 51.52 to the length IL'C between the current input electrodes 1.2) K. Then, the result is as shown in Fig. 3.That is, while the value of W/I is small, the magnetic sensation 11j B ''#iW/L K increases proportionally, but as the value of W/T, + increases, The value saturates at 8. This saturation magnetic sensitivity 8 is determined by the semiconductor's mobility II.

This saturation magnetic line [II m mm
Attempts to obtain a Hall element with a magnetic sensitivity of more than m have rarely been successful.For example, a trapezoidal Hall element such as No.
It has been theoretically and experimentally proven that the rectangular Hall element is completely equivalent to the rectangular Hall element shown in Figure 1. Since it has been proven that the magnetic field is equivalent to the element, it has been difficult to increase the magnetic sensitivity IIL by changing the element shape.

The present invention aims to provide a novel Hall element that can obtain a magnetic sensitivity higher than the saturation magnetic line [g N wa*x] obtained with the conventional rectangular Hall element shape.

In a rectangular Hall element, the reason why the magnetic sensitivity [8 violet] is saturated with respect to the value of W/L is that the Hall voltage that should theoretically occur is due to the effect of shorting the Hall voltage to the current input electrode 1.2. This is thought to be due to a decrease in Therefore, in order to obtain high magnetic sensitivity, the current input electrode 1,
2 and output electrode 51,! It is only necessary to reduce the short circuit effect with i2. The Hall element of the present invention based on such an idea is shown in FIG. 4, and FIG.
The diagram shows an example of the distribution of the thickness t- in the widthwise direction of the semiconductor chip 110 and the conductivity 11 of the semiconductor chip 110, in which the sheet resistance of the semiconductor chip 11 is large on both sides and small in the center. Therefore, the Hall output electrode 31,! Since the resistance value when looking at the current input electrode 1゜2 from both sides near $2 is large,
Hall output electrode! The Hall voltage generated at 51.52 is
Current input electrode 1.2 and Hall output electrode 31. ! Therefore, compared to the saturation magnetic sensitivity of 8I obtained from the conventional Hall element made of a rectangular semiconductor piece of uniform thickness as shown in Fig. 1, A Hall element with high magnetic sensitivity can be easily obtained according to the present invention. FIG. 6 shows another example of the film thickness distribution and conductivity distribution of the semiconductor piece 11.

FIG. 7 shows a shape of a Hall element that can further enhance the magnetic sensitivity Xt of a secondary Hall element using a semiconductor tube having the characteristics shown in FIGS. 5 and 6.

In FIG. 7, the semiconductor piece 11 has the same film thickness distribution or conductivity distribution as in FIG. 5 or @6, and
The distance between the current input electrodes 1.2 is narrow at one central portion, and wide and shaded at both sides thereof. According to this shape, both sides S close to the Hall output voltage @51°32 are
Since the current input electrodes 1.2 are further apart, the Hall voltage appearing in this vicinity is much less susceptible to being short-circuited to the current input electrodes 1,2. On the other hand, on the side i1 of and, the electric field 1t, 1! is the same as the current input electrode 1.2 is wider than the center. = is weaker than the electric field E· at the center of the element, and as a result, the local Hall electromotive force at the sides is weakened, which is a negative aspect, but overall the Hall output voltage ym becomes larger.

As mentioned above, according to the present invention, it becomes possible to easily create a Hall element with high magnetic sensitivity that could not be achieved with conventional Hall elements, and it contributes to significantly expanding the range of applications of Hall elements. be.

[Brief explanation of the drawing]

! Figure J1 is a structural diagram of a Hall element using a conventional rectangular shaped semiconductor piece with uniform film thickness and uniform sheet resistance.
The figure shows the uniform film thickness of a conventional trapezoidal shape. FIG. 5 is a diagram showing the shape dependence of the magnetic sensitivity of the Hall element of FIG. 1, and FIGS. , Figures 7, 9, and 8 show examples of the Hall element according to the present invention. IIFi is a diagram illustrating an embodiment of a Hall element with further enhanced VCA sensitivity according to the present invention. 1.2...Current input electrode 10...Conventional semiconductor piece 11 with uniform film thickness and uniform sheet resistance...With film thickness distribution or sheet resistance distribution Semiconductor piece 51.52...Hall output electrode and above Applicant Daini Seiko Co., Ltd. No. 1r! lJ ↓ Figure 2, Figure 3, Figure 7, Figure S, Figure 9, top

Claims (3)

[Claims] (1) In a Hall element in which current input electrodes are provided at both ends of a piece of material that exhibits the Hall effect, and Hall output electrodes are provided on both sides of this piece of material, the sheet resistance is large on both sides of the piece of material. , a Hall element characterized by low sheet resistance in the center. (2) The Hall element according to claim 1, wherein the material piece exhibiting the Hall effect has a thickness of % (DtM), which is thinner at both sides and thicker at the center. (3) A patent claim in which the hole-shaped material is used as a material piece, and the impurity concentration for controlling the conductivity of the material piece is made thinner on both sides and thicker in the central part. A ball element according to range 1 or 2. (4) The hole according to any one of claims 1 to 5, wherein the gap between the current input electrodes is wide at both sides and narrow at the center. element.