JPS5963776A - Semiconductor device for detecting incident position - Google Patents

Abstract

PURPOSE:To improve the sensitivity of positional detection by previously making the resistance value of the central section of the other conduction type semiconductor layer opposite to a pair of electrodes for detecting positions higher than sections in the vicinity of each electrode in the device in which the other conduction type semiconductor layer is formed on the surface of one conduction type semiconductor substeate, the electrodes are formed opposed to the other conduction type layer and the positions of particle beams projected to the surface are obtained by outputs from the electrodes. CONSTITUTION:The P type layer 3, which is thin at a central section 3a and is thick in peripheral sections 3b and 3c surrounding the section 3a, is diffused and formed to the surface of the N type semiconductor substrate 1, a light-receiving surface thereof is formed to a rectangular shape. The thickness of the central section 3a is thinned up to approximately 0.2mum while impurity concentration is also brought to 10<17>/cm<3> and resistance is brought to approximately 100kOMEGA, and the thickness of the peripheral sections 3b and 3c is brought to 1.0mum, and concentration is also brought to approximately 10<20>/cm<3> and resistance is lowered up to 100OMEGA. The positional signal electrodes 4 and 5 are formed to the layers 3b and 3c along the short sides of the resistance layer 3, and an electrode 2 is also formed to the back of the substrate 1. Accordingly, the positional resolving power of the central section of the surface is improved without shortening the full length.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises forming a semiconductor layer of another conductivity type on the surface of a semiconductor substrate of one conductivity type, and forming a pair of opposing position detection electrodes on the semiconductor layer of the other conductivity type. The present invention relates to a semiconductor device for detecting an incident position in which the position of a particle beam formed and incident on a surface is calculated from the output of the electrode.

First, the basic configuration of a semiconductor device for detecting an incident position will be explained with reference to FIG.

FIG. 1(8) is a plan view of the semiconductor device for detecting the incident position, and FIG. 1(B) is a cross-sectional view, in which the thickness direction is exaggerated. This semiconductor device for detecting an incident position is constructed by forming a resistance layer 3 made of a P-type semiconductor layer on the surface of an N-type semiconductor substrate l, and providing a pair of position signal electrodes 4 and 5 at both ends of this resistance layer. ing.

When light or particles enter the resistive layer 3, carry particles are generated, and 4% of the charge flows from the pair of electrodes 4 and 5. Since this charge is given as a function of the incident position, the incident position of light, etc. can be determined from the current flowing through the electrode.

Next, the positional resolution of the device will be explained.

FIG. 2 is a graph showing the relationship between the incident position of a particle beam or the like and the current flowing from the electrode 4.

As shown in FIG. 1, the distance between the electrode 4 and the incident point P is X,
If the current when x=Q is IAO, the current I^ flowing from the electrode 4 when the particle beam is incident at an arbitrary distance X is given by the following equation.

l ^ -IAO・'(1--x) / Shidashi:
12 is the total length of the light receiving surface.The position detection sensitivity of this device is defined as the change in the output signal with respect to the change in the position of the incident light as follows.

Position Detection Sensitivity - To ΔI/Δx-TAO/L There is a strong demand for increasing the position detection sensitivity when accurately aligning the laser beam or light spot with the semiconductor device for detecting the incident position. .

In order to increase the position detection sensitivity, the overall length can be reduced, but if the overall length is reduced, the light receiving range becomes smaller and the measurable range is sacrificed.

Therefore, reducing the total length does not provide a good solution.

An object of the present invention is to provide a semiconductor device for detecting an incident position that can satisfy the above requirements without reducing the light receiving area.

In order to achieve the above object, a semiconductor device for detecting an incident position according to the present invention includes: - forming a semiconductor layer of another conductivity type on the surface of a semiconductor substrate of conductivity type, and opposing the semiconductor layer of the other conductivity type; In the semiconductor device for detecting the incident position in which a pair of position detecting electrodes are formed and the position of the particle beam incident on the surface is calculated from the output of the electrodes, the central part of the semiconductor layer of the other conductivity type is By forming the layer with a higher resistance than the layer near each electrode, the position detection sensitivity at the center is made larger than the position detection sensitivity at the periphery.

According to the above t1η configuration, the object of the present invention can be completely achieved.

Hereinafter, the present invention will be explained in more detail with reference to the first page and the like.

FIG. 3 is a diagram showing an embodiment of a semiconductor device for detecting an incident position according to the present invention, in which FIG. 3(A) is a plan view and FIG.
) is an enlarged view in the thickness direction, similar to FIG. 1 which is a cross-sectional view.

An N-type conductive substrate 1 that can be formed into a rectangular shape that can secure a light-receiving surface of 1 mm x 2 H is prepared.

In the portion 3a of the surface resistance layer 3, ions are implanted until the impurity concentration reaches 10''/cl to form a P-type exclusive layer with relatively high resistance.

The thickness of the layer 1) in the section 3a is 0.2 μIn, and the resistance of the PH in the section 3a is 100Ω.

The impurity concentration in the peripheral parts 3b and 3c of the surface resistance layer 3 is 10.
”/cl to form a relatively low resistance layer of P-type conductivity.

The thickness of the P scraps in this peripheral area is 1.0 μm, and the resistance is 10
It is 0Ω.

A position signal electrode 4.5 is formed along the short side of the resistor @3, and the electrode 2 is connected to the bottom.

FIG. 4 shows the relationship between the incident position of a particle beam and the like and the current flowing from the electrode in the apparatus of the embodiment.

From Fig. 4, the positional resolution of the center part compared to the peripheral part -1ΔI^/
It can be easily understood that ΔX is large.

The results of actually measuring the positional resolution of the device with the above configuration will be explained.

The root mean square (ld) rms of the noise current of this device is determined in advance. The surface resistance layer 3 of the semiconductor device for detecting the incident position is irradiated with a light spot whose current flowing through the electrode 2 is 1.5 μA, and the relative position of the light spot and the surface resistance layer 3 is changed in the horizontal direction in FIG. Saseru. Then, the change ΔI in the current flowing through the electrode 4 is the root mean square of the noise current (Id
)'rms.The relative movement amount of the semiconductor device for detecting the incident position is measured using the light spot required to reach rms.

The amount of relative movement is 0.2 μm in the central portion 3a, which corresponds to 1/10000 of the total length.

For the peripheral parts 3b and 3c, 200 μrn is 1/1 of the total length.
It corresponds to 10.

When the same measurement was performed on a conventional semiconductor device for detecting the incident position of the same type (the surface resistance layer has a uniform resistance of 120 KΩ), the relative movement amount was 0.4μ.
m, which corresponds to the total length of 115,000.

However, the device according to the present invention has the advantage that the positional resolution at the center of the surface can be made greater than that of the conventional equivalent device without shortening the overall length.

[Brief explanation of the drawing]

FIG. 1(8) is a plan view of a conventional semiconductor device for detecting an incident position, and FIG. 1(B) is a cross-sectional view, with the thickness direction enlarged. FIG. 2 is a graph showing the relationship between the incident position of the particle beam and the current flowing from the electrode in the device. FIG. 3 is a diagram showing an embodiment of the semiconductor device for detecting an incident position according to the present invention, in which (Δ) is a plan view and FIG. 3 (B) is a plan view.
is a sectional view showing an enlarged view in the thickness direction. FIG. 4 is a graph showing the relationship between the incident position of a particle beam or the like and the current flowing from the electrode in the apparatus of the embodiment. 1...Semiconductor substrate 2...Electrode 3...Surface resistance layer 3a...Central part 3b, 3c of surface resistance layer...Peripheral part of surface resistance layer 4.5...Position signal electrode Patent Applicant Hamamatsu Television Co., Ltd. Agent Patent Attorney Hisashi Inoro Figure 1 Figure 22 □□9-χ Figure 3 Figure 4 Figure □ χ

Claims (1)

[Claims] (A semiconductor layer of another conductivity type is formed on the surface of a semiconductor substrate of 1,1-conductivity type, and a pair of position detection electrodes facing each other is provided on the semiconductor layer of the other conductivity type. In the semiconductor device for detecting the incident position in which the position of a particle beam formed and incident on the surface is calculated from the output of the electrode, the central part of the semiconductor layer of the other conductivity type is set to be '+Pli higher than the vicinity of each of the electrodes. A semiconductor device for detecting an incident position, characterized in that the positional resolution of the central part is larger than that of the peripheral part by forming a resistive layer. (2) The surface of the 1i*9 body substrate is The high resistance layer portion formed along the short sides of the pair of position i6 detection electrodes and formed in the central portion is surrounded by the long sides of the rectangle and sides parallel to the electrodes, respectively. A semiconductor device for detecting an incident position according to claim 1, which is formed in a quadrilateral formed in a rectangular shape. (3) The - conductivity type semiconductor substrate is N-type silicon, and the surface resistance layer is a P-type resistance layer. 2. A semiconductor device for detecting an incident position according to claim 1, wherein the peripheral portion is formed by boron diffusion and the central portion is formed by boron ion implantation.