JPH10227689A - Infrared detector and infrared focal plane array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an infrared detector having uniform output characteristics and an infrared focal plane array having satisfactory uniformity of image quality by integrating it with the detector. SOLUTION: A bolometer type infrared detector for detecting incident infrared ray comprises a first heat sensitive resistance 1 of a first heat sensitive resistor for sensing incident infrared ray, and a dummy resistance 2 of a second heat sensitive resistor for substantially causing no temperature change according to the incident ray. In this case, a difference between an electric signal changing according to the resistance value of the first resistor when the detector detects the ray and a value of an electric signal changing according to the resistance value of the second resistor is stored as a capacitance 6 in the detector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a bolometer-type infrared detector for detecting infrared radiation emitted from an object using a material whose resistance changes with temperature.

[0002]

2. Description of the Related Art In a bolometer type infrared detector, which is one of the conventional infrared detectors, infrared radiation emitted from an object is incident on a thermal resistor of the infrared detector, and the resistance of the thermal resistor changes. When the value of the bias current or the bias voltage applied to the thermal resistor changes, infrared rays are detected.

An infrared focal plane array can be formed by integrating an infrared detector two-dimensionally, arranging an infrared detector at each pixel formed in a matrix, and forming a detector array. The infrared focal plane array enables nighttime photographing or the like by extracting a scanning signal of each pixel from infrared rays incident on the detector array.

FIG. 8 shows an example of a bolometer type infrared detector as a conventional infrared detector. In FIG. 8, 90
1 is a silicon substrate, 902 is a detector, 902a and 9
02b is a support leg, 903 is a switching element, 904 is a gate signal line, 905 is a bias signal line, and 90
Reference numeral 6 denotes a reflection film.

The bolometer type infrared detector includes a silicon substrate 901, a gate signal line 904 formed on the surface of the silicon substrate 901, a bias signal line 905 orthogonal to the gate signal line 904, and a bolometer type infrared detector formed on the surface of the silicon substrate 901. The switching element 903 connected to the gate signal line 904 and the support leg 90 connected to the gate signal line 904 or the bias signal line 905 and supporting the detection unit 902
2a and 902b. The switching element 9
A reflection film 906 for increasing the absorptivity of infrared rays in the detection unit 902 is provided on a part of the surface of the optical disc 03. Also,
Although not shown, a bolometer thin film whose temperature changes when infrared rays are incident is provided on the surface of the detection unit 902. An electric signal for controlling on / off of the switching element 903 is input to the gate signal line 904.

When infrared rays are incident on the detecting section 902, the temperature of the bolometer thin film changes, the resistance of the bolometer thin film changes, and the resistance of the detecting section 902 changes. Therefore, the current value (or voltage value) of the bias signal input to the switching element 903 changes according to the amount of change in the resistance value of the detection unit 902. As a result, the current value (or voltage value) of the output signal from the switching element 903 of the bolometer-type infrared detector changes.

[0007] In order to improve the sensitivity of the bolometer type infrared detector, the bolometer thin film is made of a material having a large resistance change rate due to a temperature change. Furthermore, the bolometer-type infrared detector has a heat insulating structure that can suppress the temperature drop of the bolometer thin film due to heat transfer from the support legs to the silicon substrate using micromachining technology in order to efficiently raise the temperature of the bolometer thin film. .

[0008]

When an infrared focal plane array is formed using the above-mentioned bolometer type infrared detector, not only the sensitivity of the bolometer type infrared detector is required, but also the output is obtained. Video uniformity is required. That is, when the same infrared ray is incident on the bolometer type infrared detectors of all the pixels, it is necessary that the same output signal is obtained from all the bolometer type infrared detectors. If the difference between the output signals of the bolometer-type infrared detectors is large, a problem arises in that the quality of the output image deteriorates.

In addition, since the bolometer-type infrared detector uses the temperature change of the thermal resistor, the current value of the output signal of the bolometer-type infrared detector depends on the temperature change caused by the change of the environment surrounding the bolometer-type infrared detector. Or voltage value). Therefore, when the output signal of the bolometer-type infrared detector is amplified and output by an amplifier, it is necessary to expand the operating range of the amplifier to cope with a change in the output signal of the bolometer-type infrared detector. Therefore, there is a problem in that the range of the operating temperature is narrowed and the stability of the operation of the amplifier is reduced.

In order to solve this problem, in a conventional bolometer type infrared detector, a temperature controller is attached to an infrared focal plane array to stabilize a temperature change caused by a change in environment surrounding the bolometer type infrared detector. ing. FIG. 9 is an explanatory diagram showing an infrared focal plane array to which a temperature controller is attached. FIG.
, 910 is an infrared focal plane array,
Reference numeral 911 denotes a temperature controller. However, this solution has the problems of increasing the manufacturing cost of the infrared focal plane array and complicating the assembling process.

The present invention solves such a problem. When the same infrared rays are incident on the infrared detectors of all pixels, the output signals of the infrared detectors become the same, and a uniform image is obtained from the infrared focal plane array. It is an object of the present invention to provide an infrared detector in which the output signal of the infrared detector does not change even when the environment surrounding the bolometer-type infrared detector is changed.

[0012]

The infrared detector according to the present invention is a bolometer type infrared detector for detecting an incident infrared ray, wherein the infrared detector detects the incident infrared ray. A heat-sensitive resistor, and a second heat-sensitive resistor that does not substantially change the temperature with incident infrared light, and the resistance value of the first heat-sensitive resistor when the infrared detector detects infrared light The difference between the value of the electric signal that changes due to the change of the electric signal and the value of the electric signal that changes according to the resistance value of the second heat-sensitive resistor is stored as a capacitance in the infrared detector.

In addition, the first thermal resistor comprises a bolometer thin film, and the material of the bolometer thin film is made of amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet, CMR (colossal
magnetoresistance) and one of transition metal oxides
One.

Further, the material of the bolometer thin film is amorphous silicon.

An infrared detector according to the present invention is a bolometer-type infrared detector for detecting incident infrared light, wherein the infrared detector detects a first heat-sensitive resistor for detecting incident infrared light, A second heat-sensitive resistor that does not substantially cause a temperature change in the received infrared light, wherein the first heat-sensitive resistor and the second heat-sensitive resistor are connected in series, The difference between the potential between the thermal resistor and the second thermal resistor and the preset potential is:
It is stored as a capacity in the infrared detector.

Further, the first thermal resistor includes a bolometer thin film, and the material of the bolometer thin film is made of amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet, One of CMR and transition metal oxide.

Further, the material of the bolometer thin film is amorphous silicon.

An infrared focal plane array according to the present invention is an infrared focal plane array in which a plurality of infrared detectors are integrated, wherein the infrared detector comprises the infrared detector according to claim 1, and each pixel has The first
And the second heat-sensitive resistor are arranged.

Further, the first thermal resistor includes a bolometer thin film, and the material of the bolometer thin film is made of amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet, One of CMR and transition metal oxide.

Further, the material of the bolometer thin film is amorphous silicon.

An infrared focal plane array according to the present invention is an infrared focal plane array in which a plurality of infrared detectors are integrated, wherein the infrared detector comprises the infrared detector according to claim 4, and each pixel has The first
And the second heat-sensitive resistor are arranged.

Further, the first thermal resistor includes a bolometer thin film, and the material of the bolometer thin film is made of amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet, One of CMR and transition metal oxide.

Further, the material of the bolometer thin film is amorphous silicon.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an infrared detector and an infrared focal plane array according to the present invention will be described with reference to the drawings.

Embodiment 1 FIG. 1 is an explanatory diagram showing an equivalent circuit of a signal reading circuit including one embodiment of the infrared detector of the present invention. FIG. 1 shows a signal reading circuit including an infrared detector of the present invention and a chopper type amplifier as an amplifier for amplifying an output signal of the infrared detector. In FIG. 1, reference numeral 1 denotes a first thermal resistor which is a resistance of a first thermal resistor, 2 denotes a dummy resistor which is a resistor of a second thermal resistor, 3 denotes a current mirror circuit, 4a denotes a first switch composed of a transistor. 4b, a second switch composed of a transistor, 4c a third switch composed of a transistor, 5a a first node, 5b a second node, 5c a third node, 6 a capacitor, 7 an inverter Show. The infrared detector is shown as a first thermal resistor 1 and a dummy resistor 2 and is, for example, a bolometer-type infrared detector. The amplifier is shown as a first switch 4a, a second switch 4b, a third switch 4c, a capacitor 6, and an inverter 7.

The second thermal resistor does not substantially change the temperature with the incident infrared ray, that is, the temperature change caused by the incident infrared ray is almost equal to the resistance value of the second thermal resistor. It is a heat-sensitive resistor that does not cause a change.

Next, the operation of the signal reading circuit shown in FIG. 1 will be described.

The first thermal resistor 1 and the dummy resistor 2 are connected to a current mirror circuit 3, and the same current flows through the first thermal resistor 1 and the dummy resistor 2. When a current is applied to the first heat-sensitive resistor 1 and the dummy resistor 2 and a clock signal is applied to the first switch 4a at the same time, the first switch 4a is turned on, and the electric signal output to the first node 5a ( An electric signal which changes according to the resistance value of the dummy resistor 2 is transmitted to the capacitor 6. The terminal of the capacitor 6 on the side opposite to the side to which the first switch 4 a is connected is connected to the input section of the inverter 7. When a clock signal is applied to the second switch 4b at the same time when the electric signal is transmitted to the capacitor 6, the input and output of the inverter 7 are short-circuited, and the operating point of the amplifier can be determined.

Further, when the first switch 4a and the second switch 4b are turned off and a clock signal is applied to the third switch 4c, the third switch 4c is turned on and the output is output to the second node 5b. The transmitted electrical signal (an electrical signal that changes according to the resistance value of the first thermal resistor 1 when the infrared detector detects infrared light) is transmitted to the capacitor 6. The electric signal output to the third node 5c brings a potential equal to a potential difference between the first node 5a and the second node 5b to the third node 5c. The potential difference between the first node 5a and the second node 5b occurs according to the temperature rise corresponding to the amount of incident infrared light. The electric signal output to the third node 5c is output from the amplifier via the inverter 7.

Next, a method of manufacturing an infrared detector according to one embodiment will be described.

The first thermal resistor is formed above the substrate that supports the infrared detector while being thermally separated from the substrate by applying micromachining technology. That is,
The first thermal resistor has a structure in which the temperature changes easily by the incidence of infrared rays. On the other hand, the second thermal resistor is formed on the substrate and has the same shape as the first thermal resistor.

FIG. 2 is an explanatory sectional view showing an embodiment of the infrared detector of the present invention. In FIG. 2, reference numeral 21 denotes a first thermosensitive resistor, 22 denotes a second thermosensitive resistor, 23 denotes a silicon substrate, 24 denotes a support, 25 denotes a protective member, 26 denotes a cavity, 31 denotes a first bolometer thin film, and 32 denotes a first bolometer thin film. Indicates a second bolometer thin film.

As shown in FIGS. 2A and 2B, the first bolometer thin film 3 of the first thermal resistor 21 is formed.
1 is thermally separated from the silicon substrate 23, and a cavity 26 is formed between the support 24 and the silicon substrate 23. The second bolometer thin film 32 shown in FIGS. 2A and 2B has the same shape as the first bolometer thin film 31, that is, a thin film. It is formed on a substrate. further,
The first bolometer thin film 3 is designed so that the output of the infrared detector does not change due to a temperature change caused by a change in environment.
The resistance temperature change rate (TC) of the first and second bolometer thin films 32
It is preferred that R) have the same value. Also, the second
The thickness of the support 24 below the bolometer thin film 32 of FIG.
It may be thin as shown in FIG. 2A or thick as shown in FIG.

Even if infrared light is incident on the second bolometer thin film from the outside, the temperature change due to the infrared light is easily transmitted to the silicon substrate which is a large heat capacity member, and the resistance value of the second heat sensitive resistor is reduced by the infrared light. It does not change with the incidence. The resistance value of the second thermal resistor changes only due to a temperature change caused by a change in the environment surrounding the infrared detector. As a result, the resistance value of the first heat-sensitive resistor is determined by the temperature change caused by the incidence of infrared rays and the change of the environment, and the resistance value of the second heat-sensitive resistor is determined by the temperature change caused by the change of the environment.

When an input signal to the amplifier is generated by using an infrared detector composed of the first and second heat-sensitive resistors formed by the above-described method, it depends on the amount of incident infrared light. Thus, an input signal whose current (or voltage) changes can be obtained. In other words, it is possible to make the DC output voltage constant irrespective of the environmental temperature, and to add a signal generated by the incident infrared rays. The infrared detector can reduce a change in an output signal to the amplifier due to a temperature change caused by a change in environment.

Embodiment 2 Next, an infrared focal plane array formed using an infrared detector according to an embodiment of the present invention will be described.

The infrared focal plane array has a plurality of pixels arranged in a matrix, and one infrared detector is formed for each pixel. If the output characteristics of the infrared detectors of each pixel are not uniform, that is, even if the same infrared light is incident on the infrared detectors of all pixels, the same output signal cannot be obtained from the infrared detectors of all pixels. In this case, a uniform image cannot be obtained from the infrared focal plane array. In the conventional infrared focal plane array, in order to obtain a uniform image, the non-uniformity of the output characteristics of the infrared detector of each pixel is stored in a memory provided in the infrared focal plane array in advance, and infrared detection is performed. Techniques have been used to correct the non-uniformity of the output characteristics of the device to improve the uniformity of the image. However, this technique also has a limit on the output signal that can be corrected.

Such a problem can be solved by forming the above-described embodiment of the infrared detector of the present invention in each pixel. FIG. 3 is an explanatory diagram showing one embodiment of the infrared focal plane array of the present invention. In FIG.
Reference numeral 10 denotes an infrared detector array in which a plurality of pixels are arranged, 11 denotes a horizontal pixel selection circuit, and 12 denotes a horizontal pixel selection circuit. Note that regions A and B shown in FIG. 3 each show one pixel larger than an actual pixel for easy understanding. Generally, the size of an infrared focal plane array is several centimeters square, but the number of pixels arranged in the infrared focal plane array is tens of thousands, and the size of each pixel integrated on a large scale is several tens. μm square.

In the infrared focal plane array of the present invention, a first thermal resistor and a second thermal resistor are formed in one pixel, for example, in region A. Therefore,
Rather than forming the first and second thermal resistors separately in the regions A and B, the environment of the first and second thermal resistors is made uniform, The uniformity of the output characteristics of the infrared detector of each pixel can be improved.

One current mirror circuit as a current source for generating an input signal of the infrared detector (see FIG. 1)
In some cases, non-uniformity of output characteristics may also occur in a plurality of transistors included in the transistor. However, since the plurality of transistors included in one current mirror circuit are arranged close to each other, the non-uniformity of the output characteristics of the current source can be reduced.

FIG. 4 is an explanatory diagram showing an equivalent circuit of FIG. In FIG. 4, 1001, 1102 and 1003
Indicates an amplifier. FIG. 4 shows only 3 columns × 3 rows of pixels of all the pixels of the infrared focal plane array. Amplifiers 1001, 1102, 1
Reference numeral 003 denotes, for example, a chopper type amplifier, which is connected to the infrared detectors of vertically adjacent pixels. An area C shown in FIG. 4 shows one pixel.

In the infrared focal plane array of the present embodiment, even when a temperature change occurs due to a change in environment, the uniformity of the output characteristics of the infrared detector of each pixel is high, so that a uniform image can always be obtained. Can be.

In a conventional method of extracting a change in resistance value due to the incidence of infrared light of a bolometer type infrared detector as an electric signal, a signal reading circuit as shown in FIG. 10 is used. FIG. 10 is an explanatory diagram showing a conventional signal reading circuit. In FIG. 10, 17 is a constant current source, 18 is a node, and 19 is an output signal amplifier. As shown in FIG. 10, the first thermal resistor 1 is connected to a constant current source 1
7, the change in the resistance value of the first heat-sensitive resistor 1 due to the incidence of infrared light is regarded as the potential change at the node 18 and the amplifier 19
Can be taken out to the outside.

However, in the case of the signal reading circuit shown in FIG. 10, if the temperature changes due to a change in the environment, the resistance value of the first thermal resistor 1 changes. Therefore, even when the output signal of the signal readout circuit greatly changes due to environmental changes, it is necessary to increase the operating range of the amplifier that amplifies the output signal of the signal readout circuit so that it can operate as designed. is there. When an infrared focal plane array is formed using the signal reading circuit, a temperature controller may be attached to the infrared focal plane array so that the temperature does not change due to a change in environment.

In the present invention, similarly to the conventional signal reading circuit, the change in the amount of incident infrared light is detected by using the change in the potential between the current mirror circuit as a constant current source and the first thermal resistor. I have. However, the current mirror circuit and the first
The change in the resistance value of the first heat-sensitive resistor caused by the change in the environment is corrected by the difference between the potential between the heat-sensitive resistor and the potential between the current mirror circuit and the dummy resistor. Therefore, according to the present invention, the signal reading circuit can be less affected by environmental changes. Moreover,
Since the amplification by the amplifier starts at the operating point of the inverter, it is not necessary to increase the operating range of the amplifier.

Embodiment 3 Next, another embodiment of the infrared detector of the present invention will be described.

FIG. 5 is an explanatory diagram showing an example of an equivalent circuit of a signal reading circuit including another embodiment of the infrared detector of the present invention. FIG. 5 shows a signal reading circuit including the infrared detector of the present invention and a chopper type amplifier as an amplifier for amplifying an output signal of the infrared detector. In FIG. 5, 1 is a first thermal resistor, 2 is a dummy resistor, 4a is a first switch, 4b is a second switch, 4c is a third switch, 6 is a capacitor, 7 is an inverter, and 8a is a first switch. , 8b indicates a second node, and 8c indicates a third node.

Unlike the signal reading circuit shown in FIG. 1, a first thermal resistor 1 and a dummy resistor 2 are connected in series, and the first thermal resistor 1 is connected to a voltage source (not shown). The infrared detector and the amplifier are the first
Are connected via the node 8a.

When a voltage is applied from the voltage source to the first thermal resistor 1 and a clock signal is applied to the first switch 4a at the same time, the second thermal resistor 1 and the dummy resistor 2 are connected between the first thermal resistor 1 and the dummy resistor 2. The potential of one node 8 a is transmitted to the capacitor 6.
The opposite terminal of the capacitor 6 is connected to the input of the inverter 7. Here, when a clock signal is applied to the second switch 4b, the input section and the output section of the inverter 7 are short-circuited, and the operating point of the amplifier can be determined.

Next, when the first switch 4a and the second switch 4b are turned off and a clock signal is applied to the third switch 4c, the potential of the voltage source is applied to the capacitor 6 via the third node 8c. Convey. Therefore, the potential of the difference between the potential of the first node 8a and the potential of the second node 8b is transmitted to the third node 8c, and is output from the amplifier via the inverter 7. Note that the potential of the voltage source is
Is appropriately selected within the range that can be amplified.

According to the present embodiment, the potential input to the amplifier via the infrared detector can be freely set by changing the voltage of the voltage source.

Embodiment 4 FIG. Next, another embodiment of the infrared focal plane array of the present invention will be described. FIG. 6 is an explanatory diagram showing an equivalent circuit of another embodiment of the infrared focal plane array of the present invention. The infrared focal plane array according to the present embodiment includes the signal reading circuit shown in FIG. FIG. 6 shows only pixels of 3 columns × 3 rows among all the pixels of the infrared focal plane array, and an area D shows an infrared detector of one pixel.

In the infrared focal plane array of the present embodiment, the infrared detector comprises a first thermal resistor and a dummy resistor, and an output signal in which non-uniformity caused by a change in environment is corrected is output from a signal reading circuit. Therefore, an image with high uniformity can be obtained.

In this specification, an inverter is provided on the output side of the amplifier, but any other signal amplifier may be used. What is connected to the output terminal of the infrared detector is not limited to an amplifier. FIG. 7 is an explanatory diagram showing another example of an equivalent circuit of a signal reading circuit including another embodiment of the infrared detector of the present invention. In the signal reading circuit shown in FIG. 7, an integrator 9 is provided instead of the inverter 8 of the signal reading circuit shown in FIG. Integrator 9
Is used, the integrator 9 functions as a noise filter that can reduce noise such as thermal noise generated by the infrared detector, and can reduce the noise of the output signal of the signal reading circuit.

The infrared detector of the present invention is preferably a bolometer-type infrared detector, and the first thermal resistor comprises a bolometer thin film. Further, the material of the bolometer thin film is amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet,
It is preferably CMR (for example, perovskite-type manganese oxide) or transition metal oxide (for example, vanadium oxide), and most preferably amorphous silicon.

[0056]

According to the present invention, an infrared detector which is not affected by a temperature change caused by a change in environment can be obtained. Further, image quality can be improved by forming an infrared focal plane array using the infrared detector.

The infrared detector of the present invention is a bolometer-type infrared detector for detecting incident infrared light, wherein the infrared detector includes a first thermal resistor for detecting incident infrared light, A second heat-sensitive resistor that does not substantially change the temperature with the infrared light, and an electric signal that changes according to the resistance value of the first heat-sensitive resistor when the infrared detector detects infrared light. Since the difference between the value of the second thermal resistor and the value of the electrical signal that varies according to the resistance value of the second thermal resistor is stored as a capacitance in the infrared detector, the infrared ray is not affected by a temperature change caused by a change in environment. A detector is obtained.

Further, the first thermal resistor comprises a bolometer thin film, and the material of the bolometer thin film is made of amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet, Since it is one of the CMR and the transition metal oxide, it is made of a material having a large resistance temperature change rate (TCR), so that the sensitivity to infrared rays can be improved. The material of the bolometer thin film is amorphous silicon. This is most preferable because the first thermal resistor can be formed at the same time when the element including the semiconductor in the readout circuit is formed, and the yield can be improved.

The infrared detector of the present invention is a bolometer-type infrared detector for detecting incident infrared light, wherein the infrared detector includes a first thermal resistor for detecting the incident infrared light, A second heat-sensitive resistor that does not substantially cause a temperature change in the received infrared light, wherein the first heat-sensitive resistor and the second heat-sensitive resistor are connected in series, The difference between the potential between the thermal resistor and the second thermal resistor and the preset potential is:
Since it is stored as a capacitance in the infrared detector, an infrared detector which is not affected by temperature changes caused by environmental changes can be obtained.

Further, the first thermal resistor includes a bolometer thin film, and the material of the bolometer thin film is made of amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet, Since it is one of the CMR and the transition metal oxide, it is made of a material having a large resistance temperature change rate (TCR), so that the sensitivity to infrared rays can be improved. The material of the bolometer thin film is amorphous silicon. This is most preferable because the first thermal resistor can be formed at the same time when the element including the semiconductor in the readout circuit is formed, and the yield can be improved.

The infrared focal plane array of the present invention is an infrared focal plane array in which a plurality of infrared detectors are integrated, wherein the infrared detector comprises the infrared detector according to claim 1, and each pixel has The first
And the second thermal resistor are arranged, so that an infrared focal plane array having good uniformity of image quality can be obtained.

Further, the first thermal resistor includes a bolometer thin film, and the material of the bolometer thin film is made of amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet, Since it is one of the CMR and the transition metal oxide, it is made of a material having a large resistance temperature change rate (TCR), so that the sensitivity to infrared rays can be improved. The material of the bolometer thin film is amorphous silicon. This is most preferable because the first thermal resistor can be formed at the same time when the element including the semiconductor in the readout circuit is formed, and the yield can be improved.

An infrared focal plane array according to the present invention is an infrared focal plane array in which a plurality of infrared detectors are integrated, wherein the infrared detector comprises the infrared detector according to claim 4 and each pixel has The first
And the second thermal resistor are arranged, so that an infrared focal plane array having good uniformity of image quality can be obtained.

The first thermal resistor comprises a bolometer thin film, and the material of the bolometer thin film is made of amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet, Since it is one of the CMR and the transition metal oxide, it is made of a material having a large resistance temperature change rate (TCR), so that the sensitivity to infrared rays can be improved. The material of the bolometer thin film is amorphous silicon. This is most preferable because the first thermal resistor can be formed at the same time when the element including the semiconductor in the readout circuit is formed, and the yield can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an equivalent circuit of a signal reading circuit including one embodiment of an infrared detector of the present invention.

FIG. 2 is an explanatory sectional view showing an embodiment of the infrared detector of the present invention.

FIG. 3 is an explanatory diagram showing one embodiment of an infrared focal plane array of the present invention.

FIG. 4 is an explanatory diagram showing an equivalent circuit of FIG. 3;

FIG. 5 is an explanatory diagram showing an example of an equivalent circuit of a signal reading circuit including another embodiment of the infrared detector of the present invention.

FIG. 6 is an explanatory diagram showing an equivalent circuit of another embodiment of the infrared focal plane array of the present invention.

FIG. 7 is an explanatory diagram showing another example of an equivalent circuit of a signal reading circuit including another embodiment of the infrared detector of the present invention.

FIG. 8 is an explanatory diagram showing an example of a conventional infrared detector.

FIG. 9 is an explanatory diagram showing a conventional infrared focal plane array to which a temperature controller is attached.

FIG. 10 is an explanatory diagram showing a conventional signal reading circuit.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 first thermal resistor, 2 dummy resistor, 3 current mirror circuit, 4 a first switch, 4 b second switch, 4 c third switch, 6 capacitor, 7 inverter, 10 infrared detector array, 11 horizontal pixel selection Circuit, 12 vertical pixel selection circuit, 16 integrator.

Claims (12)

[Claims] 1. A bolometer-type infrared detector for detecting an incident infrared ray, wherein the infrared detector includes a first thermal resistor for detecting the incident infrared ray, and a temperature change in the incident infrared ray. And a second heat-sensitive resistor that substantially does not cause an electric signal that changes according to a resistance value of the first heat-sensitive resistor when the infrared detector detects infrared rays. An infrared detector, wherein a difference between a value of an electric signal that changes according to a resistance value of the resistor and a value of the electric signal is stored as a capacitance in the infrared detector. 2. The first thermal resistor comprises a bolometer thin film, wherein the material of the bolometer thin film is amorphous silicon, polycrystalline silicon, amorphous germanium, titanium,
The infrared detector according to claim 1, wherein the infrared detector is one of titanium nitride, platinum, cermet, CMR, and transition metal oxide. 3. The infrared detector according to claim 2, wherein the material of the bolometer thin film is amorphous silicon. 4. A bolometer-type infrared detector for detecting an incident infrared ray, wherein the infrared detector includes a first thermal resistor for detecting the incident infrared ray, and a temperature change in the incident infrared ray. And a second thermal resistor that substantially does not cause the first thermal resistor and the second thermal resistor are connected in series, and the first thermal resistor and the second thermal resistor are connected in series. An infrared detector, wherein a difference between a potential between the second thermosensitive resistors and a preset potential is accumulated as a capacitance in the infrared detector. 5. The first heat-sensitive resistor comprises a bolometer thin film, wherein the material of the bolometer thin film is amorphous silicon, polycrystalline silicon, amorphous germanium, titanium,
The infrared detector according to claim 4, which is one of titanium nitride, platinum, cermet, CMR, and transition metal oxide. 6. The infrared detector according to claim 5, wherein the material of the bolometer thin film is amorphous silicon. 7. An infrared focal plane array in which a plurality of infrared detectors are integrated, wherein said infrared detector comprises the infrared detector according to claim 1, and said first thermal resistor is provided for each pixel. And an infrared focal plane array, wherein the second thermal resistor is arranged. 8. The first thermal resistor comprises a bolometer thin film, wherein the material of the bolometer thin film is amorphous silicon, polycrystalline silicon, amorphous germanium, titanium,
The infrared focal plane array according to claim 7, wherein the infrared focal plane array is one of titanium nitride, platinum, cermet, CMR, and transition metal oxide. 9. The infrared focal plane array according to claim 8, wherein the material of the bolometer thin film is amorphous silicon. 10. An infrared focal plane array in which a plurality of infrared detectors are integrated, wherein said infrared detector comprises the infrared detector according to claim 4, and said first thermal resistor is provided for each pixel. And an infrared focal plane array, wherein the second thermal resistor is arranged. 11. The first thermal resistor comprises a bolometer thin film, wherein the material of the bolometer thin film is amorphous silicon, polycrystalline silicon, amorphous germanium, titanium, titanium nitride, platinum, cermet, The infrared focal plane array of claim 10, wherein the array is one of a CMR and a transition metal oxide. 12. The infrared focal plane array according to claim 11, wherein the material of the bolometer thin film is amorphous silicon.