JPS6262075B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a resistance layer of an opposite conductivity type on one side of a semiconductor substrate of a certain conductivity type, and a conversion generated by a particle beam or the like incident on the resistance layer. The present invention relates to a semiconductor device for detecting the incident position of a particle beam, etc., in which a current is divided by the resistive layer and extracted from a plurality of electrodes to detect the incident position of the particle beam, etc.

A scanning type device using television technology is widely known as a device for measuring the incident position of a light spot or a particle beam.

Recently, semiconductor devices for detecting the incident position of particle beams, etc., which are capable of detecting the incident position of particle beams, etc. without using the above-mentioned scanning, have been developed and are being used.

First, the basic configuration and operation of this semiconductor device for detecting the incident position of particle beams, etc. will be briefly explained.

FIG. 1 is a schematic diagram for explaining the configuration of a conventional semiconductor device for detecting an incident position.

FIGS. 1a, 1b, and 1c are a perspective view, a sectional view, and a plan view, respectively, of a surface-divided type semiconductor device for detecting an incident position. In the conventional surface-divided semiconductor device for detecting the incident position, as shown in each figure, a resistive layer 2 of the opposite conductivity type is formed on one surface of a semiconductor substrate 1 of a certain conductivity type. The shape of the resistance layer 2 is square or rectangular, and the resistance layer 2
Electrodes 3 are formed along the sides at a certain ratio of the length of the sides.

1d, e, and f are a perspective view, a cross-sectional view, and a cross-sectional view, respectively, of a double-sided split type semiconductor device for detecting the incident position.
and a plan view. Electrodes 3 are formed on a semiconductor substrate 1 along a pair of opposite sides of a square or rectangular resistance layer 2 having a conductivity type opposite to that of the substrate. A resistance layer 5 of the same conductivity type is formed. An electrode 4 is formed on the back surface along the opposite side orthogonal to the electrode 3 on the front surface.

The coordinate axes are set so that they pass through the center point of the square or rectangular resistance layer and are parallel to the sides of the resistance layer as shown in c and f in Figure 1, and the points where they intersect with the electrodes are set at ±1.
shall be.

Electrode 3 of surface-divided type incident position detection semiconductor device
, 3, 3, 3 are grounded, and the electrode 5
However, a voltage is applied so that the p-n junction becomes reverse biased.

Further, a bias is applied between the electrodes 3 and 3 of the double-sided split type incident position detection semiconductor device so that the pn junction is reverse biased.

When a light spot or particle beam is irradiated onto a point at arbitrary coordinates (x, y) on the resistive layer, excited carriers generated by internal effects are separated at the p-n junction.
In the surface-divided semiconductor device for detecting the incident position, one of the carriers is divided by the resistive layer 2 and flows into the electrodes 3 . The current of 3 is I ₁ , the current of 3 is I ₂ , the current of 3 is I ₃ , the current of 3 is I _{4
Then , by calculating _ _ _ _} You can get the output.

In the double-sided split type semiconductor device for detecting the incident position, p
One of the carriers separated by the -n junction flows into the electrode 3 divided by the resistance layer 2 provided on the front surface, and the other flows into the electrode 4 divided by the resistance layer 5 provided on the back surface.

By calculating X = (I ₃ - I ₁ ) / (I ₃ + I ₁ ) Y = (I ₂ - I ₄ ) / (I ₂ + I ₄ ), obtain the position output corresponding to (x, y). be able to.

The surface-split type semiconductor device for detecting the incident position and the double-side split type semiconductor device for detecting the incident position each have advantages and disadvantages that the other does not have.

Next, the position output characteristics of the semiconductor device for detecting both incident positions will be explained. Figure 2 is a graph showing the position output characteristics of both incident position detection semiconductor devices;
B shows the position output characteristics of a surface-split type semiconductor device for detecting the incident position, and FIG. Both types have a 10mm x
This is a graph of the aforementioned X and Y output characteristics obtained by moving a light spot at a constant pitch within a 10 mm area parallel to the x and y axes.

In the surface-divided semiconductor device for incident position detection shown in FIG. 2A, the light spot for measurement is moved at a constant pitch to form a grid, but the pitch of the output figure is not constant. The pitch is narrower at the periphery. On the other hand, the output characteristics of the double-sided split type semiconductor device for detecting the incident position shown in FIG. 2B have a substantially constant pitch and little distortion.

The double-sided split type semiconductor device for incident position detection has excellent output characteristics as described above, but since it is necessary to form the resistance layer 5 on the back surface of the substrate 1,
It is difficult to getter the crystal defects inside. Therefore, the junction leakage current becomes much larger than that of a surface-divided semiconductor device for detecting the incident position, reaching 10 to 100 times as much junction leakage current.
In addition, in this type of semiconductor device for incident position detection, when the position of the input (light pulse, particle, etc.) changes quickly, or when the input is a pulse, a reverse bias voltage of the p-n junction is applied in order to speed up the response of the output waveform. needs to be made larger. In the surface-split type semiconductor device for detecting the incident position, bias is applied from the back electrode of the substrate (Figure 1a), so an arbitrarily large bias voltage can be applied regardless of the amplifier connected to the electrode on the resistance layer side. is possible.

On the other hand, since a double-sided split type semiconductor device for detecting an incident position applies a bias voltage between the front and back signal electrodes, the output obtained from the signal electrodes is a combination of the signal and the bias voltage. A first method for extracting only the signal component from this output is to subtract the bias voltage component using an amplifier. At this time, since the sum of the bias voltage and the amplitude of the output signal must be lower than the operating voltage of the amplifier, the range in which the bias voltage can be set is limited.

For example, when using an operational amplifier, the bias voltage is limited to 15V or less, and the amplitude of the output signal is similarly limited.

As a second method, there is a method in which the signal electrode of the semiconductor device for detecting the incident position and the amplifier are coupled with a capacitor to cut out the DC component of the bias voltage and extract only the pulse component of the signal. It has the advantage of being able to freely set the bias voltage to a high value, but due to fluctuations in the pulse repetition period or signal strength (the output signal strength also fluctuates depending on the signal input position),
The average level of the extracted signal may fluctuate, which may impair the accuracy when calculating the position. This method is suitable when it is necessary to increase response speed even at the expense of positional accuracy.

To summarize the above, the distortion in the position output is smaller in the double-sided split type semiconductor device for detecting the incident position, but the semiconductor device for detecting the incident position with the double-sided split type has a large leakage current due to the reverse bias of the p-n junction. This means that the application method is complicated.

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to detect the incident position of a particle beam, etc. with a small leakage current, easy application of a reverse bias voltage, and small distortion of the position output. An object of the present invention is to provide a semiconductor device for use in a semiconductor device.

In order to achieve the above object, an incident position detection semiconductor device for detecting the incident position of a particle beam or the like according to the present invention includes a semiconductor substrate of a certain conductivity type and a resistive layer of the opposite conductivity type provided on one surface of the semiconductor substrate, In a semiconductor device for detecting an incident position of a particle beam, etc., in which a converted current generated by a particle beam or the like incident on the resistance layer is divided by the resistance layer and extracted from a plurality of electrodes to detect the incident position of the particle beam, etc. The resistance layer is surrounded by four arc-shaped resistance wires such that the connection points of the resistance wires are located at each corner of a square or rectangle, a current is extracted from the connection points of the resistance wires, and the extracted current is calculated to generate particles. It has an arithmetic circuit that obtains an output regarding the incident position of a wire, etc., and Ri=r□/ri (i=1,...4) between the sheet resistance value of the resistance layer and the arc-shaped resistance wire. The linear resistivity of the arc-shaped resistance wire r□ is the sheet resistance value of the resistance layer, and ri is the relationship between the radius of curvature of the arc-shaped resistance wire.

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

FIG. 3 is a plan view and a longitudinal sectional view showing an embodiment of the device according to the present invention.

This embodiment of the apparatus detects the position of a light spot.

As the semiconductor substrate 11, an n-type silicon (Si) wafer with a specific resistance of 3 to 5 kΩcm and a thickness of 200 μm is used. One surface of this semiconductor substrate 11 is mirror polished, and the other surface is sandblasted.

Phosphorus is diffused onto the sandblasted surface of the semiconductor substrate 11 to form an n-type diffusion layer 12 with a depth of 30 μm.

Next, the semiconductor substrate 11 is thermally oxidized to grow thick SiO ₂ on the entire surface, which will serve as a mask for the next boron diffusion. Next, a linear SiO ₂ film having a width of 150 μm is removed by photolithography along an arc having a radius of acm connecting the vertices of a square with a side length of 14 mm on the semiconductor substrate 1 on the mirror-polished side. Then, boron was diffused into this part by thermal diffusion, and the resistance per unit length (1 cm) in the length direction of the arc part was adjusted to be R [Ω/cm] after the completion of all steps. The resistance of this linear arc portion will be referred to as a border resistance portion 13. The semiconductor substrate 11 is oxidized again, and SiO ₂ is grown to a thickness of 5000 Å on the border resistance portion 13. Next, a hole is formed in the SiO ₂ in the area surrounded by the border resistor 13 by photolithography. At this time, the border resistance section 13 is also overlapped.
Try to remove _SiO2 . The width of the overlap is 50 μm.

This semiconductor substrate 11 was thermally oxidized, and SiO ₂ was grown to a thickness of 1500 Å on the hole.

Next, boron ions were implanted into the pattern side of the semiconductor substrate at an acceleration energy of 75 keV.

After implantation, the substrate is annealed in a _N2 atmosphere.
Ion implantation part after annealing (the border resistance 1
The sheet resistance value r of the inner part surrounded by 3)
□ (Ω/□) was adjusted so that R=r□/a.

The ion implantation section surrounded by the border resistance section 13 will be referred to as a light receiving section 14. The border resistance part 1 is placed at the apex of the four corners of the border resistance part 13.
SiO ₂ of 100μmφ without protruding from 3.
A hole was made using photolithography, and an Al electrode 15 with a diameter of 150 μm was formed concentrically. Back side of semiconductor substrate 11 (side without pattern)
Gold (Au) was vapor-deposited on the surface and alloyed with the semiconductor substrate to form an electrode on the back surface. The semiconductor substrate is diced into chips and connected to a 5-pin ceramic case by die bonding and wire bonding. The dimensions of the chip are 15 mm x 15 mm, the resistivity R of the border resistance part 13 is 12 kΩ/cm, and the radius of the arc is a.
was 2.5 cm, and the sheet resistance of the light receiving part was 30 kΩ/□.

FIG. 4 is a block diagram of an arithmetic circuit for position detection using the elements manufactured by the method described above.

_C1 to _C4 are current-voltage converters. The input potential of this current-voltage converter is set to the ground potential, and a photocurrent signal that has been photoelectrically converted flows into it, and outputs signals V ₁ to V ₄ that have been converted into voltages, respectively.

_A1 to _A5 are adders. The outputs _V2 and _V3 of the current-voltage converter are connected to the adder _A1 , and the sum signal _V2 + _V3 is output. The outputs _V1 and _V4 of the current-voltage converter are connected to the adder _A2 , and the sum signal _V1 + _V4 is output. The outputs _V1 and _V2 of the current-voltage converter are connected to the adder _A3 , and outputs the sum signal _V1 + _V2 . The outputs _V3 and _V4 of the current-voltage converter are connected to the adder _A4 , and the sum signal _V3 + _V4 is output.

The outputs of the adders A ₃ and A ₄ are connected to the adder A ₅ , and the sum signal (V ₁ +V ₂ +V ₃ +V ₄ ) is output.

The outputs of the adders A ₁ and A ₂ are connected to the subtracter S ₁ and outputs (V ₂ +V ₃ )−(V ₁ +V ₄ ). Similarly, the outputs of the adders A ₃ and A ₄ are connected to the subtracter S ₂ and outputs (V ₁ +V ₂ )−(V ₃ +V ₄ ).

The divider D ₁ sends out the following X signal output corresponding to the X coordinate of the incident point from the outputs of the subtracter S ₁ and adder A ₅ .

X = [(V ₂ + V ₃ ) - (V ₁ + V ₄ )]/(V ₁ + V ₂ + V ₃ + V ₄ ) The divider D ₂ calculates the input point from the outputs of the subtracter S ₂ and adder A ₅ . Sends the following Y signal output corresponding to the Y coordinate.

Y = [(V ₁ + V ₂ ) - (V ₃ + V ₄ )]/(V ₁ + V ₂ + V ₃ + V ₄ ) Center 10 mm x 10 of the light receiving section 14 on the element surface of the device
FIG. 5 shows the results of position calculation using the circuit configured as shown in FIG. 4 described above while moving within mm while irradiating a light spot at a constant pitch.

As is clear from FIG. 5, the pitch of the position calculation output is almost constant, and the distortion of the straight line is small.

It is clear that the position output characteristics are improved compared to conventional surface-divided semiconductor devices for detecting incident positions that have the same structure in the thickness direction of the substrate.

Next, the reason why the present invention improves the position output characteristics of the surface-divided type semiconductor device for detecting the incident position will be explained.

Assuming that a uniform resistance layer 63 is formed between two parallel electrodes extending to an infinite length as shown in FIG. 6, the x-coordinate axis is taken as shown in the figure.

Electrode 61 and electrode 62 are grounded. If the current source I is connected to the point x = x ₁ , the relationship between the electrodes I ₁ , I ₂ and x ₁ flowing into the electrodes 61 and 62 is x ₁ = (I ₂ - I ₁ ) / (I ₂ + I ₁ ).

Therefore, if we create an electrode in this state,
The linearity of the position should be the best and the position error should be zero.

By the way, as shown in FIG. 7, there is a hole with a radius of a (cm) in the uniform and infinitely wide resistance layer 72.
It is assumed that a wire resistance 71 is attached along the circumference. Let the resistivity of the wire resistance 71 be R (Ω/cm), and the sheet resistance of the resistance layer 72 be r (Ω/□). Take the x-axis so that it passes through the center O of the circle, and take the angle θ from the -x-axis. If a uniform current J (A/cm) is flowing in the x direction and is not disturbed by the circular hole, then the line resistance between θ=0 and θ= _θ1 is
A current of Ja sinθ flows into the current.

The potential drop that this current causes in the line resistance between θ=θ ₁ and θ=θ ₁ +dθ is Ja sinθ·R·adθ. Also, the projection of the circumference of dθ in the direction perpendicular to x is dx
If the potential drop is dVx, then dx=a sin
Since θdθ, dVx=Ja sinθ・r・dθ.

In order for the potential drop on the wire resistance 71 and the potential drop on the resistance layer to satisfy the assumption that the current is not disturbed, Ja sinθ・aR・dθ=Ja sinθ・r・dθ ∴ R=r/a be led out.

Now, as shown in Figure 8, the radii a12, a23, a34, a1 passing through the vertices of a rectangle with side lengths l ₁ and l ₂
There is a resistance layer 85 surrounded by an arc of 4, and the line resistivities R12, R23, R34, R
Assume that a wire resistance of 14 is attached.

Letting the sheet resistance of the resistance layer be r (Ω/□), R ₁₂ = r/a ₁₂ R ₂₃ = r/a ₂₃ R ₃₄ = r/a ₃₄ R ₁₄ = r/a ₁₄ . Connect the electrode and ground it.
Connect to the electrode and ground. Comparing this with Figure 6, we can see that Figure 8 and 6
The figures are considered equivalent.

In this way, by using the electrode structure as shown in FIG. 8, a position output without any position error can be obtained.

Since the apparatus according to the present invention is configured and operates as described above, it has the following effects.

Whereas a double-sided split type semiconductor device for incident position detection has difficulty in gettering crystal defects in the substrate and has a large dark current, the device of the present invention has a structure in the thickness direction of the substrate that allows for surface split type position detection. Since the detector is the same as the detector, the dark current is also comparable to that of a split-surface detector with the same bonding surface.

Furthermore, as for the information amount of the signal, whereas the surface-divided position detector uses photocurrent separately for X calculation and Y calculation, in the device of the present invention, both X calculation and Y calculation Since the calculation is performed using photocurrent, it is advantageous in terms of S/N compared to a surface-divided position detector.

In addition, compared to double-sided split type position detectors, since no resistance layer is formed on the back surface, the semiconductor planar process can be used for only one surface of the entire process, resulting in better mass productivity and yield.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining the configuration of a conventional semiconductor device for detecting an incident position. Figure 2 is a graph showing the position output characteristics of the semiconductor device for detecting the incident position, in which figure A is the position output characteristic of the semiconductor device for detecting the incident position of the surface split type, and figure B is the graph of the position output characteristic of the semiconductor device for detecting the incident position of the double-sided split type. 2 shows the position output characteristics of a semiconductor device. FIG. 3 is a plan view and a longitudinal sectional view showing an embodiment of a semiconductor device for detecting the incident position of a particle beam or the like according to the present invention. FIG. 4 is a circuit diagram showing an embodiment of a circuit for calculating the output of the embodiment device. FIG. 5 is a graph showing the output characteristics of the device of the embodiment. FIG. 6, FIG. 7, and FIG. 8 are explanatory diagrams for explaining the principle of the present invention. 11...Semiconductor substrate, 12...n+ diffusion layer, 1
3... Border resistance section, 14... Light receiving section, 15...
...Aluminum electrode, 16...Silicon oxide ( _SiO2 ) layer for antireflection, 17...Silicon oxide ( _SiO2 ) layer,
C ₁ to C ₄ ... Current-voltage converter, A ₁ to _{A 5} ... Adder, S ₁ , S ₂ ... Subtractor, D ₁ , D ₂ ... Divider.

Claims (1)

[Claims] 1. A semiconductor substrate of a certain conductivity type is provided with a resistance layer of an opposite conductivity type on one side, and a converted current generated by a particle beam or the like incident on the resistance layer is transferred to the resistance layer. In a semiconductor device for detecting the incident position of a particle beam, etc., which is divided into layers and taken out from a plurality of electrodes to detect the incident position of the particle beam, the resistance layer is formed of four arc-shaped resistance wires, and the connection points of the resistance wires are square. Alternatively, the resistive layer sheet has an arithmetic circuit arranged so as to be located at each corner of a rectangle, extracts a current from the connection point of the resistance wire, calculates the extracted current, and obtains an output regarding the incident position of the particle beam, etc. 1. A semiconductor device for detecting an incident position of a particle beam, etc., characterized in that it is constructed by giving the following relationship between a resistance value and an arcuate resistance wire. Ri=r□/ri (i=1,...4) where Ri is the linear resistivity of the arc-shaped resistance wire r□ is the sheet resistance value of the resistance layer ri is the radius of curvature of the arc-shaped resistance wire More than 2 The semiconductor substrate The semiconductor device for detecting the incident position of a particle beam or the like according to claim 1, wherein is of n-type. 3. The semiconductor device for detecting the incident position of particle beams, etc. according to claim 1, wherein the semiconductor device for detecting the incident position of particle beams, etc. is manufactured by a planar process. 4. A semiconductor device for detecting an incident position of a particle beam or the like according to claim 1, wherein the arithmetic circuit outputs the incident position of the particle beam as data of a coordinate point whose origin is the intersection of diagonals of the connection point.