JPH08213670A - Hall element - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a Hall element capable of performing highly sensitive magnetic field detection even if a drive terminal is displaced. An n-type epitaxial layer 12a surrounded by an isolation made of a p ⁺ -type layer 13 and two n ⁺ -type diffusion layers formed in the n-type epitaxial layer side by side at predetermined intervals in a first direction. 14a and 14b, and n ⁺ type layers 15 and 16 as output terminals formed outside in a second direction perpendicular to the first direction of the n type epitaxial layer.
In the Hall element 10 composed of and, the n ⁺ type diffusion layers 14a and 14b are formed so as to extend beyond the side edge of the n type epitaxial layer 12a in the second direction. , Hall element 10 is configured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an n-type epitaxial layer surrounded by isolation consisting of ap ⁺ -type layer and two n-type epitaxial layers formed in the n-type epitaxial layer side by side at a predetermined interval in the first direction. Two n ⁺ -type diffusion layers, and an n ⁺ -type layer as an output terminal formed outside in a second direction perpendicular to the first direction of the n-type epitaxial layer, It relates to a Hall element.

[0002]

2. Description of the Related Art Conventionally, such a Hall element is constructed as shown in FIGS. 4 and 5, for example. That is,
4 and 5, in the Hall element 1, after the low-concentration n-type epitaxial layers 3a, 3b, 3c are formed on the surface of the p-type silicon substrate 2 over the entire surface of the substrate 2, By forming ap ⁺ -type layer (isolation) 4 around the n-type epitaxial layers 3a, 3b and 3c, the n-type epitaxial layers 3a, 3b and 3c are separated, and then the n-type epitaxial layers 3a are separated. On the surface of
The n ⁺ type diffusion layers 5a and 5b are formed, and the n ⁺ type layers 6 and 7 are formed on the surfaces of the n type epitaxial layers 3b and 3c, respectively.

Further, after forming an oxide layer 8 as an insulating layer over the entire surface, windows are opened in the oxide layer 8 to the n ⁺ type diffusion layers 5a and 5b and the n ⁺ type layers 6 and 7. Provided,
It is configured by forming electrodes 9a, 9b, 9c and 9d each made of an aluminum wiring layer from above on the regions corresponding to the windows.

The Hall element 1 constructed in this way is
^{The *} type diffusion layers 5a and 5b act as drive terminals, and the n ⁺ type layers 6 and 7 act as output terminals, respectively. Then, by applying a predetermined input voltage to the n ⁺ type diffusion layers 5a and 5b, the n type epitaxial layer 3a is provided between the n ⁺ type layers 6 and 7 as output terminals.
In the region between the n ⁺ type diffusion layers 5a and 5b, a voltage corresponding to the vertical magnetic field is generated. That is, when the magnetic field in the region does not act, n ⁺ -type diffusion layer of n ⁺ -type diffusion layer 5a is a driving terminal is driven pin 5
The drive current to b flows straight in the n-type epitaxial layer 3a as shown by the arrow A.

On the other hand, when a magnetic field acts on the above-mentioned region, the n ⁺ -type diffusion layer 5a which is the drive terminal changes from the n ⁺ -type diffusion layer 5b which is the drive terminal depending on the magnitude of the magnetic field. As shown by the arrow B, the driving current of (1) is curved and flows in the n-type epitaxial layer 3a. As a result, the current density in the above region changes, so that the potential gradient between the n ⁺ type layers 6 and 7 which are output terminals changes. Therefore, between the n ⁺ type layers 6 and 7, that is, the electrodes 9c and 9d
In the meantime, a voltage corresponding to the magnitude of the magnetic field is generated. Thus, by measuring this voltage, the magnitude of the magnetic field can be detected.

[0006]

However, in the Hall element 1 having such a structure, the positional accuracy of the n ⁺ -type diffusion layers 5a and 5b with respect to the n-type epitaxial layer 3a in the manufacturing process is determined by the n-type epitaxial layer. by placing a mask on the 3a, the n ⁺ -type diffusion layer 5a by diffusion from above, because it forms a 5b, the n ⁺ -type diffusion layer 5a,
The positional accuracy of 5b with respect to the n-type epitaxial layer 3a is
It will be determined based on the tolerance of the mask alignment.

By the way, even within the range of the mask alignment tolerance, the n ⁺ -type diffusion layers 5a and 5b are n
When a displacement occurs with respect to the epitaxial layer 3a,
As shown in FIG. 6, the drive current flowing in the n-type epitaxial layer 3a has a slight deviation. Therefore, the n ⁺ type diffusion layers 5a, 5 of the n type epitaxial layer 3a
Even if the magnetic field does not act on the region between b, an unbalanced voltage exists between the n ⁺ type layers 6 and 7 which are output terminals, so that highly sensitive magnetic field detection is performed. There was a problem that I could not get it.

In view of the above points, the present invention has an object to provide a Hall element capable of performing highly sensitive magnetic field detection even if the drive terminals are displaced.

[0009]

According to the present invention, the above object is to provide an n-type epitaxial layer surrounded by an isolation of ap ⁺ -type layer and a predetermined direction in the n-type epitaxial layer in the first direction. Two n ⁺ type diffusion layers formed side by side with an interval, and an n ⁺ type layer as an output terminal formed outside in a second direction perpendicular to the first direction of the n type epitaxial layer. And an n ⁺ -type diffusion layer formed in the first direction is formed so as to extend beyond the side edge of the n-type epitaxial layer in the second direction. This is achieved by the Hall element.

The Hall element according to the invention is preferably
The n ⁺ -type diffusion layer formed in the first direction is formed so as to extend beyond the side edge of the n-type epitaxial layer in the second direction, larger than the tolerance of mask alignment in the manufacturing process. There is.

[0011]

According to the above structure, since the n ⁺ type diffusion layer as the drive terminal extends beyond the side edge of the n type epitaxial layer in the second direction, it is possible to manufacture the n ⁺ type diffusion layer. Even if displacement occurs in the second direction within the mask alignment tolerance, with respect to the width of the region in which the drive current flows from one drive terminal to the other drive terminal of the n-type epitaxial layer, Vignetting due to this displacement can be reduced.

Therefore, the driving current flowing in the n-type epitaxial layer is hardly biased. Therefore, when no magnetic field acts on the n-type epitaxial layer in the region between the n ⁺ -type diffusion layers, the output terminal No unbalanced voltage is generated between the n ⁺ -type layers. Thus, when a magnetic field acts on the area, the magnetic field can be detected with high sensitivity.

The n ⁺ -type diffusion layer, which is the drive terminal, is formed so as to extend beyond the side edge of the n-type epitaxial layer in the second direction, larger than the tolerance of mask alignment in the manufacturing process. In this case, even if the n ⁺ -type diffusion layer is misaligned with respect to the n-type epitaxial layer in the second direction due to the mask alignment tolerance, one of the driving terminals of the n-type epitaxial layer is moved to the other. Vignetting due to this positional shift can be completely eliminated with respect to the width of the region where the drive current flows to the drive terminal.

Therefore, the above-mentioned drive current is not biased at all, and the magnetic field can be detected with higher sensitivity.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings. FIG. 1 shows an embodiment of the Hall element according to the present invention. In FIG. 1, the Hall element 1
0 indicates the surface of the p-type silicon substrate 11 with respect to the substrate 1.
Low concentration n-type epitaxial layer 1 over the entire surface of 1
After forming 2a, 12b and 12c, ap ⁺ type layer (isolation) 13 is formed around the n type epitaxial layers 12a, 12b and 12c to separate the n type epitaxial layers 12a, 12b and 12c. To do.
Here, the n-type epitaxial layers 12a, 12b, 12
c is the n-type epitaxial layers 12b, 12 on the outer side in the vertical direction in FIG.
c is arranged. Then, on the surface of the n-type epitaxial layer 12a, n ⁺ -type diffusion layers 14a and 14b arranged in the left-right direction at predetermined intervals in FIGS. 1 and 2 are formed, and the n-type epitaxial layers 12b and 12c are formed.
The n ⁺ type layers 15 and 16 are formed on the surfaces of the respective layers.

Further, after forming an oxide layer 17 as an insulating layer over the entire surface, windows are opened in the oxide layer 17 to the n ⁺ type diffusion layers 14a and 14b and the n ⁺ type layers 15 and 16. Electrodes 18a, 18b, 1 made of aluminum wiring layers are provided on the regions corresponding to the windows.
It is configured by forming 8c and 18d.

The above structure is similar to that of the conventional Hall element 1 shown in FIGS. 4 and 5, but in the Hall element 10 according to the embodiment of the present invention, the n ⁺ type diffusion layer 14 is used.
a, 14b are laterally, that is, n ⁺ type layers 15, 16
In the direction in which are aligned, the width of the n-type epitaxial layer 12a extends beyond the width thereof. In this case, the n ⁺ type diffusion layer 14
The side edges of a and 14b are preferably formed so as to extend beyond the side edges of the n-type epitaxial layer 12a by a dimension equal to or larger than a mask alignment tolerance in the manufacturing process.

The Hall element 10 according to the present invention is configured as described above, and the n ⁺ type diffusion layers 14a and 14b serve as drive terminals, and the n ⁺ type layers 15 and 16 serve as output terminals, respectively. It will be. Then, the above n ⁺
By applying a predetermined input voltage to the type diffusion layers 14a and 14b, the n ⁺ type layer 15 serving as an output terminal,
A voltage corresponding to the magnetic field acting in the vertical direction is generated between 16 in the region between the n ⁺ type diffusion layers 14a and 14b of the n type epitaxial layer 12a. Thus,
By measuring the voltage between the electrodes 18c and 18d, the magnitude of the magnetic field can be detected.

In this case, within the mask alignment tolerance when forming the n ⁺ type diffusion layers 14a and 14b,
When the n ⁺ type diffusion layers 14a and 14b are laterally displaced with respect to the n type epitaxial layer 12a, as shown in FIG. 3, the n ⁺ type diffusion layers 14a and 14b are the n type epitaxial layers. The effective portion overlapping with 12a acts as a drive terminal. Therefore, the effective drive terminal is
Since the n ⁺ type diffusion layers 14a and 14b are defined by the side edges of the n type epitaxial layer 12a instead of the side edges of the n ⁺ type diffusion layers 14a and 14b, even if the n ⁺ type diffusion layers 14a and 14b are laterally displaced, The effective drive terminal does not shift to the side. Therefore, from the n ⁺ type diffusion layer 14a on one side to the n ⁺ type diffusion layer 14 on the other side through the n type epitaxial layer 12a.
The drive current flowing in b hardly causes deviation.

At this time, the side edges of the n ⁺ -type diffusion layers 14a and 14b preferably extend beyond the side edges of the n-type epitaxial layer 12a by a dimension larger than the tolerance of mask alignment in the manufacturing process. When formed, the effective displacement of the drive terminal due to the lateral displacement of the n ⁺ type diffusion layers 14a and 14b is completely eliminated.

In addition, n ⁺ type layers 15 and 1 as output terminals
6, n ⁺ -type layer 14a, since it is 14b formed simultaneously, n ⁺ -type layer 14a, and 14b i.e. valid drive pin,
The positional deviation between the n ⁺ type layers 15 and 16 which are the output terminals can be eliminated.

Thus, when the magnetic field does not act on the region between the n ⁺ type diffusion layers 14a and 14b of the n type epitaxial layer 12a, between the n ⁺ type layers 15 and 16 which are output terminals, that is, between the electrodes 18c and 18d. Since an unbalanced voltage is not generated, a highly sensitive magnetic field can be detected based on the output voltage between the electrodes 18c and 18d.

[0023]

As described above, according to the present invention, since the n ⁺ type diffusion layer which is the drive terminal extends beyond the side edge of the n type epitaxial layer in the second direction, n ⁺ Even if the positional deviation occurs in the second direction within the tolerance of mask alignment in manufacturing the type diffusion layer, driving from one drive terminal of the n-type epitaxial layer to the other drive terminal is performed. Vignetting due to this positional shift can be reduced with respect to the width of the region where the current flows.

Therefore, since the driving current flowing in the n-type epitaxial layer is hardly biased, when the magnetic field does not act on the n-type epitaxial layer in the region between the n ⁺ type diffusion layers, the output terminal No unbalanced voltage is generated between the n ⁺ -type layers. Thus, when a magnetic field acts on the area, the magnetic field can be detected with high sensitivity.

Thus, according to the present invention, it is possible to provide an extremely excellent Hall element in which highly sensitive magnetic field detection can be performed even if the drive terminals are displaced.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an embodiment of a Hall element according to the present invention.

FIG. 2 is a schematic sectional view of the Hall element of FIG.

FIG. 3 is a schematic plan view in the case where the drive terminals of the Hall element of FIG. 1 are displaced.

FIG. 4 is a schematic plan view showing an example of a conventional Hall element.

5 is a schematic sectional view of the Hall element of FIG.

FIG. 6 is a schematic plan view showing a case where the drive terminals of the Hall element of FIG. 4 are displaced.

[Explanation of symbols]

10 semiconductor device 11 p-type silicon substrate 12a n-type epitaxial layer 12b, 12c n-type epitaxial layer 13 p ⁺ type layer 14a, 14b n ⁺ type diffusion layer (driving terminal) 15, 16 n ⁺ type layer (output terminal) 17 oxidation Layers 18a, 18b, 18c, 18d Electrodes

Claims (2)

[Claims] 1. An n-type epitaxial layer surrounded by an isolation formed of a p ⁺ -type layer, and two n ⁺ -type diffusion layers formed in the n-type epitaxial layer side by side at a predetermined interval in a first direction. And an n ⁺ -type layer as an output terminal formed outside in a second direction perpendicular to the first direction of the n-type epitaxial layer. A hall element, wherein the n ⁺ type diffusion layer formed in one direction is formed so as to extend beyond the side edge of the n type epitaxial layer in the second direction. 2. The n ⁺ type diffusion layer formed in the first direction is larger than the tolerance of mask alignment in the manufacturing process in the second direction and extends beyond the side edge of the n type epitaxial layer. 2. The hall element according to claim 1, wherein the hall element is formed on the surface of the hall element.