JP2002280600A - Semiconductor position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PSD capable of suppressing the deterioration of distance detection accuracy on a short-distance side and on a long-distance side. SOLUTION: The PSD comprises a main resistance region PN from both ends of which the different currents can be extracted depending on a light incident position on a photosensitive region. The main resistance region PN comprises a wide first resistance region R1, a narrow second resistance region R2 and a wide third resistance region R3, which are formed continuously. In the photosensitive region, there is only a small change in light incident position on the long-distance side, however, the small change in light incident position can be detected accurately since the second resistance region R2 is narrow. Furthermore, the effect of the third resistance region suppresses the deterioration of the distance detection accuracy caused by the decrease of an S/N ratio. Since the third resistance region R3 is wider relative to the second resistance region R2, even if the incident light misses the second resistance region, a length enough to collect electric charges generated in the second resistance region can be obtained, suppressing the deterioration of the distance detection accuracy caused by missing of the incident light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor position detector (PSD).

[0002]

2. Description of the Related Art A semiconductor position detector (PSD) is known as an apparatus for measuring the distance of an object to be measured by using the so-called triangulation principle or the like. The PSD is mounted on an imaging device such as a camera as an active distance measuring device, and in such an imaging device, focusing of a photographic lens is performed based on a distance of an object to be measured measured by the PSD.

In the above-mentioned PSD, the position of the incident light spot on the photosensitive region of the PSD moves according to the distance to the object to be measured. The output current is distributed in inverse proportion to the resistance value from the incident light spot position to the both ends of the resistive layer and is output from the signal extraction electrodes at both ends of the resistive layer, so the distance to the DUT is detected based on the output current. can do.

However, when the distance is measured using the principle of the triangulation method, the position of the incident light spot largely moves on the photosensitive area when the distance to the object at a short distance changes. When the distance to the object at a long distance changes, the position of the incident light spot does not move much. That is, in this case, the accuracy of detecting the distance to the object to be measured at a long distance is lower than the accuracy at the short distance.

If the width of the resistive layer on the far side is narrower than the width of the resistive layer on the near side of the photosensitive region, the amount of movement of the incident light spot from the object to be measured at a long distance is small. Also, the resistance division ratio of the resistance layer greatly changes. Therefore,
In this case, it is possible to improve the accuracy of detecting the distance to the object at a long distance. Such a PSD is described, for example, in JP-A-4-240511.

[0006]

However, in the PSD described in the publication, the width of the resistance layer is increased linearly from the far side to the short side, that is, the width of the resistance layer is increased. Although the output signal change is increased by narrowing linearly from the short distance side to the long distance side, the resistance region becomes narrower, that is, on the long distance side,
Since the intensity of light incident from the measurement object is low, and the width is reduced, the signal on one side output from the PSD is further reduced, so that the S / N ratio is reduced and the distance detection accuracy by the PSD is reduced. In addition, when light is incident on the end of the resistive layer where the output signal change is the largest, part of the light goes out of the photosensitive region, and the distance detection accuracy is reduced due to lack of incident light. That is, even if the width of the resistance region is reduced on the short distance side in order to improve the distance detection accuracy, there is a problem that the S / N ratio decreases and the distance detection accuracy decreases due to lack of incident light.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a PSD capable of suppressing a decrease in distance detection accuracy at a short distance and a long distance.

[0008]

In order to solve the above-mentioned problems, a semiconductor position detector (PSD) according to the present invention comprises a main resistance region in which different currents are taken from both ends according to an incident light position on a photosensitive region. Wherein the main resistance region includes a wide first resistance region, a narrow second resistance region, and a wide third resistance region, each having substantially the same resistivity.
The resistance region is continuous along the position detection direction.

[0009] The position of the incident light moves on the light-sensitive area according to the distance of the object to be measured. The direction in which the incident light moves on the photosensitive region is defined as a position detection direction. The charges generated in response to the irradiation of the photosensitive region with the incident light are collected by the branch conductive layer and flow into the main resistance region. Alternatively, it is collected directly in the main resistance region. That is, the light incident position in the photosensitive region changes according to the position of the device under test, and the current drawn from both ends of the main resistance region changes correspondingly, so that the distance from the current to the device under test is detected. Will be done.

Here, the main resistance region is composed of a wide first resistance region, a narrow second resistance region, and a wide third resistance region having substantially the same resistivity, which are continuous in the position detection direction. Do it. The incident light from the object at a short distance is the first
It is arranged so as to be incident on the photosensitive region on the resistance region side.

[0011] Electric charges generated by light from the object to be measured on the short distance side are collected by the nearby branched conductive layer, and the first electric charges are collected.
When flowing into the resistance region or directly collecting at the first resistance region, the first resistance region is relatively wide, so that the resistance change accompanying the movement of the incident position is small, but the change in the distance of the DUT is small. Accordingly, the position of the incident light largely moves, so that the distance can be accurately detected.

When the object moves to the second resistance region side along the position detection direction by moving the object to the far side, the charge generated by light from the object to be measured at the far side Is collected by the neighboring branch conductive layer and flows into the second resistance region, or is collected directly in the second resistance region. In this case, the position of the incident light moves small according to the change in the distance of the object to be measured, but since the second resistance region is relatively narrow, the resistance change accompanying the movement of the incident position is large, and therefore, accurately. Distance detection can be performed.

Further, when the object to be measured further moves to the far distance side, and the incident position protrudes from the second resistance region along the position detecting direction, the electric charge generated by the protruding light is changed to a nearby branch conductive material. It is collected at the layer and flows into the third resistance region or is collected directly at the third resistance region.
In this case, even if a part of incident light having a finite size deviates from the second resistance region, the third resistance region can contribute to position detection. Further, even when the intensity of the incident light is reduced due to the object to be measured being at a long distance, the third
The resistance region can suppress an excessive decrease in signal output in the second resistance region, and the third resistance region is relatively wide, so that it is necessary to cope with incident light protruding from the second resistance region. The length can be secured. Therefore, it is possible to suppress the deterioration of the distance detection accuracy.

Here, it is preferable that the main resistance region is linearly connected between the two ends, and that a plurality of branch conductive layers extend from a plurality of positions of the main resistance region. In this case, the main resistance region functions as a main conductive layer extending along the position detection direction. The branch conductive layer is connected to the base conductive layer and extends over the sensitive region. The branch conductive layer collects charges generated by the incident light and propagates the charge to the base conductive layer. The position can be detected.

The main resistance region has a linear connection between the two ends, and a plurality of other main resistance regions having the same structure as the main resistance region are provided in parallel with the main resistance region. Is preferred. In this case, the main resistance region group forms a stripe, and the charges generated corresponding to the incident light are directly collected in each main resistance region, and the first, second, and third electric charges of each main resistance region are collected. In the resistance region, as in the case described above, the light is extracted from both ends of each main resistance region so as to be inversely proportional to the resistance value from the light incident position to both ends of the main resistance region.

Further, the main resistance region may be connected in a meandering manner between both ends so as to represent a triangular waveform. Electric charges generated in response to the incident light are directly collected in each main resistance region, and the first and second electric charges of the main resistance region are collected.
Similarly, in the third resistance region, the light is extracted from both ends of the main resistance region so as to be inversely proportional to the resistance value from the light incident position to both ends of the main resistance region in the same manner as described above.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor position detector (PSD) according to an embodiment will be described below.

The same reference numerals are used for the same elements or elements having the same functions, and duplicate descriptions are omitted.

(First Embodiment) FIG. 1 is a plan view of a PSD according to a first embodiment, and FIG. 2 is a plan view of the PSD shown in FIG.
FIG. 3 is a sectional view of the PSD shown in FIG.
It is III arrow sectional drawing. The cross-sectional view of the PSD used for the description shows the end face. Although the PSD includes a passivation film 5 on the front surface side (FIGS. 2 and 3), the description of the passivation film 5 is omitted in FIG. 1 and the plan views of the PSD according to the following embodiments.

This PSD includes a semiconductor substrate 2n made of low-concentration n-type Si and a back-side n-type semiconductor layer 1n made of high-concentration n-type Si formed on the back surface of the semiconductor substrate 2n. The surface of the semiconductor substrate 2n is rectangular. In the following description, the extension direction of the long side of the rectangular surface of the n-type semiconductor substrate 2n is the length direction (longitudinal direction: position detection direction) X, the extension direction of the short side is the width direction Y, the length direction X, and the width direction. A direction perpendicular to both Y is defined as a depth direction (thickness direction) Z. That is, the directions X, Y, and Z are orthogonal to each other.

The PSD includes a basic conductive layer (main resistance region) PN made of p-type Si and formed in the semiconductor substrate 2n and extending along the length direction X. The basic conductive layer PN is
A plurality of p-type resistance regions P1 to P30 are continuous along the length direction X of the PSD and are formed in the n-type semiconductor substrate 2n. Each of the resistance regions P1 to P30 has substantially the same impurity concentration, and extends from the surface of the n-type semiconductor substrate 2n to substantially the same depth along the thickness direction Z. Each of the resistance regions P1 to P30 has substantially the same resistivity ρ
Having.

The surface of each of the resistance regions P1 to P30 is rectangular, and two opposing sides of the rectangular surface are parallel to the X direction, and the other two sides are parallel to the Y direction. Note that the main conductive layer PN
Are the first resistance region (R1 = P12 to P30), the second resistance region (R2 = P5 to P11) and the third resistance region (R3 =
P1 to P4) are continuous in the X direction. R1, R2, R
3 resistance regions P12 to P30, P5 to P1
1, P1 to P4 have a constant width in each region.

Each of the resistance regions P5 to P1 of the second resistance region R2
1 is the length of each resistance region P1 of the first resistance region R1.
The lengths in the Y direction are substantially the same as the lengths in the X direction of 2 to P30, and the lengths in the Y direction are shorter than the lengths in the Y direction of the resistance regions P12 to P30 of the first resistance region R1. Each resistance region P1 to P of the third resistance region R3
4 is substantially the same as the length of each of the resistance regions P12 to P30 of the first resistance region R1 in the X and Y directions.
Therefore, the contour of the surface of the main conductive layer PN as a whole has a shape in which three rectangles including the first, second, and third resistance regions R1, R2, and R3 are combined so as to be continuous in the longitudinal direction.

The region on the semiconductor substrate 2n where charges (carriers) are generated by light incidence is a light-sensitive region.
D is a PSD having a main conductive layer (main resistance region) PN from which both different currents are extracted from both ends according to the position of incident light on the photosensitive region, and the main conductive layers PN each have substantially the same resistance. Wide first resistance region R having a rate ρ
1 (P12 to P30) and the narrow second resistance region R2 (P5
To P11) and the wide third resistance region R3 (P1 to P3).
4) is continuous along the position detection direction X.

The position of the incident light moves on the light sensitive area according to the distance of the object to be measured. The moving direction X of the incident light on the light sensitive area is a position detection direction. The charges generated in response to the irradiation of the photosensitive region with the incident light are collected by the branching conductive layer 4PN near the incident position described later, and
Flows into. The electric charge flowing into the main conductive layer PN is taken out as a current from both ends of the main conductive layer PN so as to be inversely proportional to the resistance value from the light incident position to both ends of the main resistance region, and the distance from the current to the object to be measured is detected. Will be done.

Here, the first resistance region R1, the second resistance region R2, and the third resistance region R3 which form the basic conductive layer PN.
Have substantially the same resistivity, which are continuous along the position detection direction. The wide first resistance region R1 (P12 to P30) side is arranged on the short distance side.

When the charge generated by the light from the object to be measured on the short distance side flows into the first resistance region R1 (P12 to P30), it is relatively wide, so that it is accompanied by the movement of the incident position. Although the resistance change is small, the position of the incident light largely moves in accordance with the change in the distance of the object to be measured, so that the distance can be accurately detected.

When the object to be measured moves to a far distance side, the incident position is shifted along the position detection direction to the second resistance region R2.
Side, the charges generated by the light from the object to be measured on the long distance side are charged by the second resistance region R2 (P5 to P1).
Flow into 1). In this case, although the position of the incident light moves slightly according to the change in the distance of the device under test, the second resistance region R2
Since (P5 to P11) are relatively narrow, the resistance change accompanying the movement of the incident position is large, so that the distance can be accurately detected.

Further, when the object to be measured further moves to the far distance side, and the incident position protrudes from the second resistance region R2 (P5 to P11) along the position detection direction, the charge generated by the protruding light. Are collected by a branched conductive layer near the incident position, which will be described later, and are collected by the third resistance region R3 (P1 to P3).
P4). In this case, a part of incident light having a finite size is reduced in the width of the second resistance region R2 (P5 to P11).
, The function of the third resistance region R3 (P1 to P4) suppresses a decrease in distance detection accuracy. Further, even when the intensity of the incident light decreases due to the object to be measured being at a long distance, the excessive output of the signal in the second resistance region R2 (P5 to P11) is generated by the third resistance region R3 (P1 to P4). Can be suppressed, and the third resistance region R
3 (P12 to P30) are wide, so the second resistance region R2
It is possible to secure a length necessary to cope with incident light protruding from (P5 to P11). Therefore, deterioration of the S / N ratio and the distance detection accuracy can be suppressed.

It should be noted that a PSD having a shape similar to that of JP-B-7
-83133. This PSD is
The miniaturization is achieved by connecting a narrow resistance area as a non-detection area (non-incident area) to a wide resistance area as a light-sensitive area. Is essentially irrelevant.

The present PSD includes a pair of signal extraction electrodes 1e and 2e formed at both ends of the surface of the PSD to extract output currents from both ends of the main conductive layer PN.

This PSD includes a plurality of branched conductive layers 4PN made of high-concentration p-type Si extending from the basic conductive layer PN along the photosensitive region.

The plurality of branched conductive layers 4P1 to 4P29 forming the branched conductive layer 4PN are formed in the n-type semiconductor substrate 2n, and extend from between the plurality of resistance regions P1 to P30 forming the basic conductive layer PN. It extends along the width direction Y. The branch conductive layers 4P1 to 4P29 extend along the thickness direction Z from the surface of the n-type semiconductor substrate 2n to a position deeper than the depth of the main conductive layer PN, and extend in the width direction Y of the branch conductive layers 4P1 to 4P29. The length is the same. The charge generated by the light incident on the photosensitive region is collected by the branch conductive layer 4PN, flows into the connection part of the main conductive layer PN, and is inversely proportional to the resistance value from the connection part to both ends of the main conductive layer. Since the current is taken out from both ends of the base conductive layer PN as a current, the distance from the current to the object to be measured can be detected.

The present PSD includes a pair of high-concentration signal extraction semiconductor layers formed in a semiconductor substrate 2n, each of which is continuous with both ends of a basic conductive layer PN in which resistance regions P1 to P30 are continuous in the length direction X. 1p and 2p. The high-concentration signal extraction semiconductor layers 1p and 2p are made of high-concentration p-type Si. The high-concentration signal extraction semiconductor layers 1p and 2p are formed on the semiconductor substrate 2n.
Extends from the surface along the thickness direction Z to a position deeper than the depths of the resistance regions P1 to P30.

The semiconductor layers 1p and 2p for extracting a high concentration signal are
Each has a rectangular surface, the long sides of which are parallel to the width direction Y and the short sides thereof are parallel to the length direction X. Both ends of the main conductive layer PN are connected to the high-concentration signal extraction semiconductor layers 1p and 2p, respectively, with one end of the long side of the rectangular surface of the high-concentration signal extraction semiconductor layers 1p and 2p as a boundary.

In other words, the length direction X of the main conductive layer PN
Is connected to one end along the width direction Y of one high-concentration signal extraction semiconductor layer 1p, and the resistance region P1 extends along the length direction of the main conductive layer PN. X
, That is, the resistance region P30 is connected to one end along the width direction Y of the other high-concentration signal extraction semiconductor layer 2p.

The present PSD includes an outer frame semiconductor layer 3n formed on the outer peripheral portion of the rectangular surface of the semiconductor substrate 2n. The outer frame semiconductor layer 3n is high-concentration n-type Si. The outer frame semiconductor layer 3n is formed in the outer edge region of the rectangular surface of the semiconductor substrate 2n to form a square shape, and forms the branch conductive layer 4PN, the main conductive layer PN, and the high concentration signal extraction semiconductor layers 1p and 2p. And extends from the surface of the n-type semiconductor substrate 2n to a predetermined depth along the thickness direction Z.

In the present PSD, the branched conductive layer isolation semiconductor layer 4nN formed in the semiconductor substrate 2n is aligned. The branching conductive layer isolating semiconductor layer 4nN is a high concentration n-type Si. The branched conductive layer isolating semiconductor layer 4nN includes a plurality of n-type branched regions extending inward from the inside of the two long sides of the square-shaped outer frame semiconductor layer 3n along the width direction Y in the base conductive layer PN direction. 4n1-4
n30. Each of the branch regions 4n1 to 4n30 extends from the surface of the n-type semiconductor substrate 2n to a predetermined depth along the thickness direction Z.

The basic conductive layer PN and the branched conductive layer 4P
The N and high concentration signal extraction semiconductor layers 1p and 2p may be integrally formed and have the same impurity concentration and the same depth.

The n-type branch regions 4n2 to 4n29 forming the isolation semiconductor layer 4nN are composed of p-type branch conductive layers 4P1 to 4P1.
4P29 having substantially the same depth as the branch conductive layers 4P1 to 4P4.
The branch conductive layers 4P1 to 4P29 are interposed between the P29s to electrically isolate them. That is, the branch regions 4n2 to 4n2
9 blocks a current flowing along the length direction X between adjacent ones of the branch conductive layers 4P1 to 4P29.

The outermost branch regions 4n1 and 4n1
n30 is the outermost branched conductive layers 4P1 and 4P29 along the length direction X and the high-concentration signal extracting semiconductor layers 1p and 4p.
2p and the branch conductive layers 4P1, 4P
29 and the high-concentration signal extraction semiconductor layers 1p and 2p are electrically isolated from each other.

The passivation film 5 has a pair of rectangular openings for signal extraction electrodes at both ends in the length direction, and a square-shaped opening for an outer frame electrode at the outer periphery. Signal extraction electrode 1
e and 2e are formed on the high-concentration signal extraction semiconductor layers 1p and 2p, respectively, through a pair of openings for signal extraction electrodes of the passivation film 5, and the high-concentration signal extraction semiconductor layers 1p and 2p, respectively. Ohmic contact with 2p.
The surface shapes of the signal extraction electrodes 1e and 2e are the same as the surface shapes of the high-concentration signal extraction semiconductor layers 1p and 2p.

The present PSD has an outer frame electrode 3e formed on the n-type outer frame semiconductor layer 3n through an opening for the outer frame electrode of the passivation film 5. The outer frame electrode 3e is in ohmic contact with the outer frame semiconductor layer 3n. Outer frame electrode 3e
Prevents light from entering the outer peripheral portion of the semiconductor substrate 2n. Further, a predetermined voltage can be applied between the outer frame electrode 3e and the signal extraction electrodes 1e and 2e.

The present PSD has a lower surface electrode 4e formed on the lower surface of the back side n-type semiconductor layer 1n. Lower electrode 4e
Are in ohmic contact with the back side n-type semiconductor layer 1n.

A reverse bias voltage is applied between a pair of signal extraction electrodes 1e, 2e and lower electrode 4e to a pn junction diode composed of p-type branched conductive layer 4PN and n-type semiconductor substrate 2n. When an incident light is incident as a spot light on the photosensitive region defined by the surface region of the n-type semiconductor substrate 2n on which the branched conductive layer 4PN is formed in a state where a proper voltage is applied, the PSD inside the PSD is changed in accordance with the incident light. Then, a hole-electron pair (carrier: charge) is generated, one of which is collected in the branched conductive layer 4PN according to the electric field inside the diffusion and PSD.

This electric charge is conducted through the branched conductive layer 4PN and flows into a predetermined resistance region of the basic conductive layer PN, and the electric charge is changed according to the position of the predetermined conductive region PN in the longitudinal direction X. The amount is distributed, and the distributed charges are extracted from the signal extraction electrodes 1e and 2e via both ends of the main conductive layer PN.

In the following description, output currents respectively output from the signal extraction electrodes 1e and 2e in accordance with the incidence of incident light on the light-sensitive region are denoted by I1 and I2, respectively.

FIG. 4 shows the concept of a distance measuring device using the PSD 100 shown in FIG. 1, and this distance measuring device can be provided in an imaging device such as a camera. This distance measuring device has a PSD of the following embodiment instead of the PSD shown in FIG.
Any of these may be used. This distance measuring device is a PSD10
0, a light emitting diode (LED) 101, a light projecting lens 102, a light collecting lens 103, and an arithmetic circuit 104.

The PSD 100 is arranged such that its length direction X is parallel to a line segment defined by the distance (base line length) B between the optical axes of the lenses 102 and 103, and the signal extraction electrode 1e is used for signal extraction. It is arranged so as to be closer to the optical axis of the lens 103 than the electrode 2e. Also, lens 1
The distance f between the light-sensitive areas 02 and 103 and the light-sensitive area of the PSD 100 substantially corresponds to the focal length of the lenses 102 and 103.

It should be noted that on the optical axis of the condensing lens 103, a light-sensitive region coincident with the end of P5 of the second resistance region R2 of the main conductive layer PN is located.

The light emitted from the LED 101 is transmitted through the projection lens 102 to the object O at a short distance (L1).
When illuminated on B1, reflected light from the measured object OB1 is incident on the near side of the photosensitive region of the PSD via the condenser lens 103, that is, on the side closer to the signal extraction electrode 2e of the photosensitive region, Collected in the nearby branched conductive layer 4PN. The reflected light from the object OB2 at a long distance (L2) passes through the condenser lens 103 toward the far side of the photosensitive region of the PSD, that is, the one closer to the signal extraction electrode 1e of the photosensitive region. The incident light is collected on the nearby branched conductive layer 4PN.

The incident position X1 of the light reflected by the object OB1 at a short distance onto the photosensitive region is determined by the condensing lens 10
The distance X1 from the optical axis of the PSD along the lengthwise direction X of the PSD to the distance X1. 1
It is located at a distance X2 from the optical axis 03 along the length direction X of the PSD. Further, the total length of the main conductive layer PN in the length direction X is C.

FIG. 5 shows an incident light position X by the PSD.
6 is a graph showing a relationship between (μm) and actually measured photocurrents I1 and I2 (μA). Here, the total length of the main conductive layer PN is 1.5 mm (1500 μm), and the center position in the length direction X of the main conductive layer PN is a reference position (X = 0).

FIG. 6 shows the incident light position X by the PSD.
6 is a graph showing a relationship between (mm) and ideal relative photocurrent outputs I1 and I2 (%). The relative photocurrent output is
This is the ratio of the output currents I1 and I2 from both ends of the main conductive layer PN to the total output current I1 + I2. In addition, the X of the first resistance region R1, the second resistance region R2, and the third resistance region R3.
The direction lengths are 0.95, 0.35, and 0.2 mm, respectively.

The arithmetic circuit 104 outputs the output currents I1 and I2
From the ratios R1 = I1 / (I1 + I2) and R2 = I2 /
After calculating (I1 + I2), the position X, which is a function of the ratios R1 and R2, is calculated, and the distance L corresponding to the position X in the memory that stores a table indicating the relationship between the distance L and the position X calculated in advance. By searching for, the distance L can be obtained. These relationships may be measured in advance by actual measurement, but a predetermined calculation formula calculated from actual measurement or theoretical value can also be used. If the relational expression is determined in advance, the calculation method calculated by the calculation circuit 104 can calculate the distance L according to the relational expression.

(Second Embodiment) FIG. 7 is a plan view of a PSD according to a second embodiment. In this PSD, the main resistance region PN has a linear connection between both ends,
The PSD is provided in parallel with the main resistance region PN, and includes a plurality of other main resistance regions PN having the same structure. In this case, the main resistance region group PN forms a stripe, and the charges generated in response to the incident light are:
The first, second, and third resistance regions R1, R2, and R3 of each main resistance region PN are directly collected by the main resistance regions near the incident position.
At R3, as in the case described above, current is taken out from both ends of the main resistance region PN so as to be inversely proportional to the resistance value from the light incident position to both ends of the main resistance region PN.

In this embodiment, the branch conductive layer does not exist, and the isolation semiconductor layer 4nN is interposed between the main resistance regions PN and blocks a current flowing between the main resistance regions PN in the Y direction.

(Third Embodiment) FIG. 8 is a plan view of a PSD according to a third embodiment. In this PSD, the main resistance region PN connects the both ends in a triangular waveform. The charges generated in response to the incident light are directly collected by the main resistance regions near the incident position, and the first, second, and third resistance regions R1, R2, and R3 of each main resistance region PN are different from those described above. Similarly, current is extracted from both ends of the main resistance region PN so as to be inversely proportional to the resistance value from the light incident position to both ends of the main resistance region PN.

It should be noted that also in this example, there is no branching conductive layer, and the isolation semiconductor layer 4nN is formed in a region other than the region where the main resistance region PN is formed. To block the current flowing through.

Although the main resistance region PN has a triangular waveform in the above description, various meandering shapes such as a square waveform or a sine waveform can be adopted.

[0061]

As described above, as described above, the PSD of the present invention is used.
Can suppress a decrease in distance detection accuracy on the short distance and long distance sides.

[Brief description of the drawings]

FIG. 1 is a plan view of a PSD according to a first embodiment.

FIG. 2 is a cross-sectional view of the PSD shown in FIG. 1 taken along the line II-II.

FIG. 3 is a sectional view of the PSD shown in FIG. 1 taken along the line III-III.

FIG. 4 is an explanatory diagram showing a distance measuring device using the PSD 100 shown in FIG. 1;

FIG. 5 is a graph showing a relationship between an incident light position X (μm) by the PSD and actually measured photocurrents I1 and I2 (μA).

FIG. 6 is a graph showing a relationship between an incident light position X (mm) by the PSD and ideal relative photocurrent outputs I1 and I2 (%).

FIG. 7 is a plan view of a PSD according to a second embodiment.

FIG. 8 is a plan view of a PSD according to a third embodiment.

[Explanation of symbols]

4e: lower surface electrode, 3e: outer frame electrode, PN: main resistance region (basic conductive layer), 1e, 2e: signal extraction electrode, R1, R
2, R3: first, second, and third resistance regions, OB1: measured object, OB2: measured object, 2n: semiconductor substrate, 3n: outer frame semiconductor layer, 1p, 2p: semiconductor layer for extracting a high concentration signal , 4
nN: isolation semiconductor layer, 4PN: branching conductive layer, 5: passivation film, 102: light projecting lens, 103: light collecting lens, 104: arithmetic circuit.

Claims (4)

[Claims] 1. A semiconductor position detector comprising a main resistance region from which both different currents are extracted from both ends according to an incident light position on a light-sensitive region, wherein the main resistance regions have substantially the same resistivity. Wherein the wide first resistance region, the narrow second resistance region, and the wide third resistance region having the following structure are continuous along the position detection direction. 2. The semiconductor device according to claim 1, wherein the main resistance region has a linear connection between both ends thereof, and a plurality of branch conductive layers extend from a plurality of positions of the main resistance region. 2. The semiconductor position detector according to 1. 3. The main resistance region includes a plurality of main resistance regions having the same structure as the main resistance region in parallel with the main resistance region. The semiconductor position detector according to claim 1, wherein: 4. The semiconductor position detector according to claim 1, wherein the main resistance region is connected while meandering between the both ends.