JP3441405B2 - Semiconductor infrared detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor infrared detecting element capable of detecting infrared rays by using a semiconductor pn junction, a semiconductor infrared detecting device and a semiconductor infrared imaging device equipped with this element, and further semiconductor infrared detecting. The present invention relates to a method of manufacturing an element.

[0002]

2. Description of the Related Art A method for measuring a temperature using a pn junction has already been put into practical use as a temperature sensor for measuring low temperature in a liquid nitrogen temperature region or the like, but it is a point sensor and the size of the sensor is several mm. It was only realized as a corner and a relatively large sensor. However, the recent development of micromachining technology and high quality and large area SOI (Silico
With the availability of nOn Insulator) substrates, it has become possible to apply this principle to semiconductor infrared imaging devices.

Since the semiconductor infrared image pickup device has a detection principle that the temperature difference of the object to be photographed is received by the sensor heat sensitive portion and the temperature change of the heat sensitive portion is converted into an electric signal, the area of the heat sensitive portion can be minimized. Increasing the size leads to higher sensitivity. However, the area of the heat sensitive part is, for example, 50 μm.
When a standard optical system with a temperature difference of 0.1 ° C. of the object to be imaged is used as a corner, only a few mK changes in the heat-sensitive part. Therefore, a signal which is less than 1/100 of that of the conventional point sensor can be obtained.

Further, in the semiconductor infrared image pickup device, the sensor as the semiconductor infrared detection element is, for example, 320 × 240.
The size of one sensor is 50 μm
Even in terms of corners, the pixel area becomes 16 mm × 12 mm, and the aperture of the optical system increases accordingly. From the trade-off between sensitivity and pixel area, one pixel area is 50
The μm angle is considered to be the maximum. At present, there is a strong demand for increasing the number of pixels and reducing the size of the optical system, and in the future, the area of one pixel will be reduced.

On the other hand, as an example of a semiconductor infrared detecting element using a pn junction, a signal voltage is increased by forming a plurality of pn junctions in series in one heat-sensitive section by using a fine processing technique. , It has been proposed to make the noise sufficiently larger than the noise generated in the heat-sensitive part itself (Japanese Patent Laid-Open No. 9-
166497, Proc. Of SPIE 3563 (1999)). This example is shown in FIG. 210 in the figure is a Si substrate 211,
An SOI substrate including a SiO ₂ film 212 and a p-type Si layer (SOI layer) 213, 214 is an n-type diffusion layer, 215 is a diode formed of a pn junction, 216 is a connection wiring between the diodes, and 218 and 219 are for external connection. , 220 is a heat sensitive part, 221 and 222 are support legs, and 230 is a hollow part.

However, in this structure, since the region for converting heat into an electric signal is limited to the pn junction, a sufficient temperature rise of the sensor portion can be obtained even though sufficient light energy is incident. Absent. Therefore, it has been found that it is difficult to obtain a highly sensitive semiconductor infrared detecting element.

In general, in an imaging device using a pn junction, it is necessary to suppress the dark current value in order to detect the voltage increase by using the reverse characteristic of the pn junction, so that the junction area is large. I didn't have to. Furthermore, a technique for increasing the junction area is used in a solar cell using a pn junction, but this also uses the reverse characteristics of the pn junction, and small elements are connected in series to increase the output voltage. This is done in order to avoid arranging a high-concentration impurity-added layer on the surface where sunlight is incident, and is different from the structure in which part of the n-type is projected.

[0008]

As described above, in the conventional semiconductor infrared imaging device, the sensitivity increases with the increase of the heat-sensitive portion, but the increase of the heat-sensitive portion causes various problems. Due to the demand for reduction of the optical system and the like, the heat-sensitive portion tends to be reduced, and thus it has been difficult to obtain a sufficiently high sensitivity.

The present invention has been made in consideration of the above circumstances, and an object thereof is to improve the sensitivity without enlarging the heat-sensitive portion, and to provide a highly sensitive and responsive semiconductor. It is to provide an infrared detection element.

Another object of the present invention is to provide a semiconductor infrared detecting device and a semiconductor infrared imaging device using the above semiconductor infrared detecting element. Still another object of the present invention is to provide a method for manufacturing the above semiconductor infrared detecting element.

[0011]

(Structure) In order to solve the above problems, the present invention adopts the following structure.

That is, according to the present invention, in a stacked pn junction type semiconductor infrared detecting element, a heat sensitive portion including a pn junction portion formed in a form of being laminated on a semiconductor layer on an insulator and having a joint surface formed in an uneven shape, A hollow structure is used to thermally separate the semiconductor substrate from the semiconductor substrate, except that the periphery is contacted by at least one support leg, and a forward bias voltage is applied to the pn junction to increase the temperature of the heat sensitive portion. It is characterized in that the current flowing through the pn junction that changes in response to the detected current is detected, and infrared rays are detected based on the change in the detected current.

Further, according to the present invention, in a stacked pn junction type semiconductor infrared detecting device, a pn junction portion formed in a form of being laminated on a semiconductor layer on an insulator and having a joint surface formed in an uneven shape, and this pn junction portion. A heat sensitive part thermally separated from the semiconductor substrate by a hollow structure, and a voltage applying means for applying a forward bias voltage to the pn junction, except that the periphery is contacted by at least one supporting leg. And a current detecting unit that detects a current flowing through the pn junction that changes according to the temperature of the heat-sensitive unit, and detects infrared rays based on a change in the current detected by the current detecting unit. .

Further, according to the present invention, in a stacked pn junction type semiconductor infrared imaging device, a pn junction portion formed in a form laminated on a semiconductor layer on an insulator and having a joint surface formed in an uneven shape, and this pn junction portion. And a plurality of heat-sensitive parts that are thermally separated from the semiconductor substrate by a hollow structure except that the periphery is contacted by at least one support leg.
Dimensionally arranged heat sensitive section array and pn of each heat sensitive section
It comprises a voltage applying means for applying a forward bias voltage to the junction portion, and a current detection means for respectively detecting a current flowing through the pn junction portion which changes according to the temperature of each of the heat sensitive portions. It is characterized in that an infrared image is picked up based on a change in the detected current by the means.

The present invention also relates to stacking a semiconductor layer on an insulator.
From the semiconductor substrate including the pn junction formed in
Has a heat-sensitive part that is electrically isolated,
To detect the current that flows when an ass voltage is applied
Stacked pn junction type semiconductor used for more infrared detection
In the method of manufacturing the infrared detection element,
Predetermined mask for the semiconductor layer formed via the edge film
The joint surface is made concave by ion implantation and diffusion using
Process of forming convex pn junction and this pn junction
The heat-sensitive part including the contact part is connected to the surroundings by at least one support leg.
Apart from being touched, it is thermally separated from the semiconductor substrate by the hollow
As shown in Fig.
Selectively etching the substrate below the portion
It is characterized by

Here, the following are preferred embodiments of the present invention. (1) The pn junction part should be formed continuously in the heat sensitive part. (2) The pn junction is electrically separated in the heat-sensitive portion and is connected in series.

(3) The cross-sectional shape of the pn junction surface of the pn junction changes periodically. (4) The cross-sectional shape of the pn junction surface of the pn junction changes into a sawtooth waveform. (5) The change in the pn junction surface of the pn junction is in a lattice shape when viewed from the semiconductor layer surface direction.

(Function) According to the present invention, the pn junction area can be increased without increasing the volume of the heat-sensitive portion by forming the joint surface of the pn junction portion in an uneven shape. Therefore, while the largest thermal noise component as the noise component of the heat-sensitive part is reduced, the heat capacity of the heat-sensitive part is not increased, so that a semiconductor infrared detection element having high sensitivity and good responsiveness can be obtained. Moreover, since a cooling mechanism is not required, it is possible to reduce power consumption. Then, it becomes possible to achieve high sensitivity, low power consumption, and high-speed response of a semiconductor infrared detection device or a semiconductor infrared imaging device using this element.

[0019]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below with reference to the illustrated embodiments.

(First Embodiment) FIG. 1 is for explaining a semiconductor infrared imaging device according to the first embodiment of the present invention. FIG. 1A is a plan view showing an arrangement example of a heat-sensitive section,
(B) is a plan view showing the configuration of one heat-sensitive portion, and (c) is a cross-sectional view showing the configuration of the same heat-sensitive portion (cross section taken along the line AA 'in (b)).

As shown in FIG. 1A, the heat sensitive parts 20 are arranged in a matrix, and each heat sensitive part 20 is provided with a wiring 18.
It is connected to the vertical address line 31 via the line and is connected to the horizontal address line 32 via the line 19. The size of the heat sensitive portion (pixel) 20 is 50 μm × 50 μm, and 2
56 pixels × 256 pixels are arranged two-dimensionally. As shown in FIG. 1B, each heat sensitive portion 20 is supported by two support legs 21 and 22, and is thermally separated from the substrate and other heat sensitive portions. Wirings 18 and 19 made of Ti are formed on the support legs 21 and 22 to connect the heat-sensitive portion 20 and the address lines 31 and 32.

The specific structure of the heat sensitive section 20 is as shown in FIG. That is, a p-type Si layer 13 having a film thickness of 0.3 μm is formed on the Si substrate 11 via the SiO ₂ film 12 to form an SOI substrate, and the SOI layer (p-type Si layer) 13 of the SOI substrate is About 0. from the surface except the periphery.
By forming the n-type diffusion layer 14 up to 1 μm, a pn junction that becomes the heat-sensitive portion 20 is formed. The n-type diffusion layer 14 is about 0.2 μm from the surface toward the p-type Si layer 13.
In other words, the joint surface is formed in a saw-tooth wave shape in cross section, and the pn junction area is about 1.3 times as large as that in the case of having a normal flat surface.

The SOI layer 13 and the SiO ₂ film 12 are removed around the heat sensitive portion 20 except for the supporting legs 21 and 22, and the Si substrate 11 under the heat sensitive portion 20 is removed to a predetermined depth. That is, the heat sensitive portion 20 is thermally separated from the substrate and other heat sensitive portions by the hollow structure portion 30.

An insulating film 15 is formed on the surfaces of the SOI layer 13 and the n-type diffusion layer 14, a contact hole is formed in a part of the insulating film 15, and a p-side electrode 16 and an n-side electrode 17 are provided respectively. There is. The wiring 19 is connected to the p-side electrode 16 and the wiring 18 is connected to the n-side electrode 17.

Here, as an example of a method of forming the n-type diffusion layer 14, as shown in FIG. 2A, the p-type S of the heat-sensitive portion 20 is formed.
Square masks 25 of 0.25 μm × 0.25 μm are two-dimensionally arranged on the i layer 13 at a pitch of 0.5 μm, and arsenic is ion-implanted. Then, by diffusion by heat treatment or the like, a pn junction having a sawtooth cross section is formed as shown in FIG.

In order to form the heat sensitive portion 20 separately, the steps shown in FIG. 3 are adopted. In this figure, the n-type diffusion layer 14
The electrodes 16 and 17 and the like are omitted. First, FIG.
As shown in (a), a mask 26 is formed on the SOI layer 13. The mask 26 is formed so as to have an opening around the heat sensitive portion 20 except for the support legs 21 and 22. That is, the heat sensitive portion 20, the support legs 21, 22, and the address line 3
A mask 26 is formed so as to cover the regions where the 1, 32 are arranged.

Then, as shown in FIG. 3B, RIE is performed.
Then, the SOI layer 13 is selectively etched by the method shown in FIG.
As shown in FIG. 5, the SiO ₂ film 12 is selectively etched by RIE. As a result, the heat sensitive part 20 is separated from the other heat sensitive parts. Next, as shown in FIG. 3D, wet etching is performed to expose the (111) surface of the Si substrate 11. As a result, the heat sensitive section 20
Will be separated from the substrate 11.

When the element of this embodiment is used for detecting infrared rays, as shown in FIG. 4, for example, a variable voltage source 4 for applying a forward bias voltage to the pn junction of the heat sensitive section 20.
1 is connected, and the forward current flowing through the pn junction is detected by the current detector 42. Further, the output level of the variable voltage source 41 changes based on the detection result of the current detector 42 as described later.

When a forward bias voltage is applied to the pn junction, a forward current flows in the pn junction, but the voltage dependence of this forward current is sufficiently larger than that of the reverse current. As a result, the difference in forward current (difference in output) before and after the incidence of infrared rays, that is, the absolute value of the detection signal also increases, and the signal / noise ratio (S / N ratio) can be obtained. Therefore, the output difference can be easily detected by the detection means (not shown), so that the detection performance can be improved.

When a drift current is detected by the current detector 42, the variable voltage source 41 changes its output level so that a forward current of a level that cancels the drift current flows. As a result, even if a drift current is generated, the output of the pn junction becomes an output only by the current generated by infrared irradiation, so that infrared can be detected even if a drift current occurs. In addition,
The reverse bias voltage may be applied to the pn junction by a constant voltage source instead of the variable voltage source 41 only for the purpose of improving the detection performance, that is, if the problem of drift current is not considered.

In the present embodiment, the size of the pixel is 50 μm × 50 μm and 256 pixels × 25 as described above.
Six pixels are arranged two-dimensionally. The pixel size is 50
Although the size is μm × 50 μm, the area of the heat sensitive portion 20 excluding the regions of the supporting legs and the peripheral vertical-horizontal address lines 31 and 32 is only 1350 μm ² . If the pn junction area is simply increased, the area of the heat sensitive portion is increased. Then, the heat capacity of the heat sensitive unit 20 increases, and the response speed decreases.

However, according to the present embodiment, the pn junction area is 1755 μ without increasing the heat capacity of the heat sensitive section 20.
m ² and the forward bias voltage is 0.5 V
When applied, the current is about 5μA and the thermal noise is about 5μA.
It will be about V. Temperature fluctuation noise is 1 as other noise component
μV, current shot noise 2μV, low frequency noise 0.1
It becomes about μV. The total noise voltage is about 8.1V and f /
1. NE when measured using an optical system with a transmittance of 65%
The TD (noise transmission temperature difference) was about 0.08K.

For example, the bonding area is set to 135 without using the present invention.
When the device manufactured with 0 μ ² was measured in the same manner, the current when a forward bias voltage of 0.5 V was applied was about 3 μ.
A, the thermal noise is about 8 μV. As other noise components, temperature fluctuation noise is 1 μV and current shot noise is 2
μV and low frequency noise are about 0.1 μV. The total noise voltage was about 11.1 μV, and the NETD was about 0.23K when measured using an optical system with f / 1 and a transmittance of 65%.

As described above, according to the present embodiment, the heat sensitive portion 2
By forming the junction surface of the pn junction portion of 0 in a sawtooth wave cross section, the pn junction portion is increased without increasing the capacitance of the heat sensitive portion 20.
The joining area can be increased. That is, the heat sensitive part 20
While the largest thermal noise component as a noise component is reduced, the heat capacity of the heat sensitive unit 20 is not increased, so that it is possible to achieve high sensitivity and low power consumption of the semiconductor infrared imaging device.

Further, since the forward bias voltage is applied to the pn junction, a large forward current can be passed as compared with the reverse current, and the output current can be increased. As a result, the difference between the forward currents before and after the incidence of infrared rays, that is, the absolute value of the detection signal also increases, and the signal / noise ratio (S / N ratio) can be obtained, so that the detection performance can be improved. Further, since the heat sensitive portion 20 is thermally insulated by the cavity (hollow structure portion) 30, it becomes possible to prevent the occurrence of drift current due to the change in ambient temperature.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention.
It is a figure which shows typically the principal part (detection part structure) of the semiconductor infrared imaging device which concerns on embodiment of this. The parts corresponding to those in FIG. 4 are designated by the same reference numerals, and detailed description thereof will be omitted.

The present embodiment is a more specific version of the detection unit of the first embodiment. The current detector 42 is composed of a first differential amplifier 51 and a resistor 52, and the variable voltage source 41 is It comprises a low-pass filter 53, a second differential amplifier 54, and a constant voltage source 55.

When a drift current occurs, the output of the first differential amplifier 51 changes accordingly. In particular,
In the output of the first differential amplifier 51, a low-frequency, large-amplitude component (drift component) appears as compared with the original detection signal.

This drift component is low-pass filter 53.
And is input to the-terminal of the second differential amplifier 54. Here, since the + terminal of the second differential amplifier 54 is connected to the constant voltage source 55, the second differential amplifier 54 outputs a voltage of a level corresponding to the drift current.

The output of the second differential amplifier 54 is input to the + terminal of the first differential amplifier 51. Here, the negative terminal of the first differential amplifier 54 is the n-type diffusion layer 14 of the heat sensitive unit 20.
Therefore, the first differential amplifier 54 outputs the original detection signal obtained by subtracting the output corresponding to the drift current from the output of the heat sensing unit 20. That is, in the output of the first differential amplifier 51, a low-frequency component corresponding to the drift current and a large-amplitude signal component do not appear.

(Third Embodiment) FIG. 6 shows a third embodiment of the present invention.
FIG. 3 is a cross-sectional view showing the configuration of a heat-sensitive part of the semiconductor infrared imaging device according to the embodiment. The same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The present embodiment differs from the first embodiment described above in the shape of the n-type diffusion layer 14. In this embodiment, an SOI substrate having an SOI layer 13 having a film thickness of 0.5 μm is used, and phosphorus and arsenic are diffused by ion implantation using the same mask as in the first embodiment. The accelerating voltage during arsenic ion implantation is 90 keV and a junction is formed to a depth of 0.3 μm. Phosphorus is introduced to 0.1 μm at an acceleration voltage of 40 keV and diffused to form a junction in the region under the mask.

As a result, a deep junction as shown in FIG. 6 can be formed in a part, and the junction area is increased by about 1.8 times. When the same measurement was performed, the NETD was improved to about 0.05K.

(Fourth Embodiment) FIG. 7 is a view for explaining a semiconductor infrared imaging device according to a fourth embodiment of the present invention. FIG. 7A is a plan view showing the structure of one heat-sensitive section,
(B) is sectional drawing which shows the structure of a heat-sensitive part (A- arrow of (a).
A'section). The same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, the SOI layer 13 is separated into, for example, six by the element isolation oxide film 71, and the n-type diffusion layer 74 is selectively formed in each of the separated SOI layers 13. That is, a pn junction is formed in each of the separated SOI layers 13. And the separated SO
The I layer 13 is connected so that the respective pn junctions are connected in series.

With such a structure, the area of the pn junction can be increased without increasing the area of the heat sensitive section 20, and the same effect as that of the first embodiment can be obtained. That is, there is an advantage that the output voltage can be increased.

(Fifth Embodiment) FIG. 8 shows a fifth embodiment of the present invention.
It is a figure which shows the circuit structure of the uncooled thermal infrared imaging device which concerns on embodiment of this.

The unit cell is composed of one diode 101 _i (i
= 1, 2, 3, 4) and one MOS transistor (read transistor) 113 _i (i = 1, 2, 3, 4), and such a unit cell is, for example, in a 2 × 2 matrix. Are formed in an array. As the diode 101 _i , the heat sensitive part shown in FIG. 1, FIG. 6, or FIG. 7 can be used.

Each MOS transistor 113 ₁ , 113 ₂
Gates are connected to a row selection line (vertical address line) 114 ₁ , one source / drain is connected to each column selection line (horizontal address line) 115 _{1 and} 115 ₂ , and the other source / drain is a diode. 101 ₁ ,
It is connected to the cathode of 101 ₂ .

Similarly, each MOS transistor 113 ₃ ,
The gates of 113 ₄ are both connected to the row selection line 114 ₂ .
One source / drain is the column selection line 115, respectively.
_{1, 1} 15 ₂ and the other source and drain are connected to the diodes 101 ₃ and 101 ₄ , respectively.

The column selection lines 114 ₁ and 114 ₂ are connected to the vertical address circuit 116. On the other hand, the row selection line 115
₁ , 115 ₂ are connected to the horizontal address circuit 118 via MOS transistors (selection transistors) 117 ₁ , 117 ₂ , respectively.

The gates of the MOS transistors 117 ₁ and 117 ₂ are connected to the horizontal address circuit 118. Further, one of the sources and drains of the MOS transistors 117 ₁ and 117 ₂ is the column selection lines 115 ₁ and 115 ₂ , respectively.
And the other source and drain are both connected to the output line 11
9 is connected. The output line 119 is connected to the first differential amplifier 106. Further, the second differential amplifier 109 is connected to the anode of the diode 101 _i .

In the device thus configured, the vertical address circuit 116 sets the potential of _one row selection line (for example, the row selection line 114 ₁ ) to the on level, and the two MOS transistors connected to the same row selection line ( For example MOS
When the transistors 113 ₁ and 113 ₂ ) are turned on, the two diodes (for example, the diodes 101 ₁ and 101 ₂ ) connected to the same MOS transistor are electrically connected to the column selection lines 115 ₁ and 115 ₂ , respectively.

Next, when the horizontal address circuit 118 sequentially turns on the MOS transistors 117 ₁ and 117 ₂ , two diodes (for example, the diode 101) are turned on.
The outputs of ₁ , 101 ₂ ) are sequentially input to the first differential amplifier 106 via the output line 119. As a result, the effect of drift current on the average output of the _two diodes (eg diodes 101 ₁ , 101 ₂ ) is eliminated,
The output of the second differential amplifier 109, in other words, the inputs of the anodes of the two diodes are feedback-controlled.

Next, when the potential of the other row selection line (for example, the row selection line 114 ₂ ) is set to the on level by the vertical address circuit 116, this time the average of the remaining two diodes (for example, the diodes 101 ₃ , 101 ₄ ) is set. The output of the second differential amplifier 109, in other words the input of the anodes of the two diodes, is feedback-controlled so that the influence of the drift current on the output is eliminated.

By repeating the above operation,
Four diodes 101₁~ 101 _FourRegarding the average output of
So that the effect of drift current can be removed.
Output of width device 109, in other words four diodes 10
1₁~ 101_FourFeedback control of the anode input
To be done. In this way, the drift current component is removed
And four diodes 101₁~ 101_FourThe average output of
It is controlled so that it falls within a certain range.

In the present embodiment, the case where the unit cells are arranged in a matrix of 2 × 2 has been described.
Other matrix shapes, for example, a matrix shape of 4 × 4 or 4 × 5 or the like, or a matrix shape of several hundreds × several hundreds may be used. Further, instead of forming the matrix in a two-dimensional array, the linear array may be formed in a one-dimensional array.

(Sixth Embodiment) FIGS. 9 and 10 are diagrams showing the circuit arrangement of an uncooled thermal semiconductor infrared imaging device according to the sixth embodiment of the present invention. The same parts as those in FIG. 8 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the fifth embodiment, the diodes 101 ₁ ...
Although the input of the anode of 101 ₄ is feedback-controlled, in the present embodiment, the potential of the output line 19 is feedback-controlled so that the four diodes 101 ₁ ...
The average output of 101 ₄ is controlled so that it falls within a certain range. Even in this case, the same effect as that of the fifth embodiment can be obtained.

(Seventh Embodiment) FIG. 11 is a view showing the essential parts (detection part structure) of an uncooled thermal semiconductor infrared detector according to the seventh embodiment of the present invention.

In the present embodiment, the output of the diode 101 which is irradiated with infrared rays and is used for actual detection, and the reference which is set so that a constant forward current flows by the constant current source 120 without being irradiated with infrared rays. Infrared rays are detected by comparing the output of the diode 101ref with the differential amplifier 106 having the feedback resistor 107.

In this case, the diodes 101 and 101ref
Infrared can be detected with high sensitivity and high accuracy by making the same structure as shown in FIG. 1, FIG. 6 or FIG.

The present invention is not limited to the above embodiments. In the embodiment, the heat-sensitive part is supported by the two support legs, but it is also possible to support it by one support leg. Further, the shape of the pn junction surface is not limited to that shown in FIG. 1C or FIG. 6 and may be any shape having irregularities so as to increase the area. Furthermore, the number and arrangement of the heat sensitive parts,
It can be changed appropriately according to the specifications. In addition, various modifications can be made without departing from the scope of the present invention.

[0064]

As described above in detail, according to the present invention, p
By forming the joint surface of the n-joint in an uneven shape,
It is possible to increase the pn junction area without increasing the volume of the heat-sensitive part, which makes it possible to realize a semiconductor infrared detection element having high sensitivity and good responsiveness. By using this element, it is possible to improve the sensitivity and the high-speed response of the semiconductor infrared detection device and the semiconductor infrared imaging device.

[Brief description of drawings]

FIG. 1 is a plan view showing an arrangement example of a heat-sensitive portion and a cross-sectional view showing the configuration of the heat-sensitive portion, for explaining the semiconductor infrared imaging device according to the first embodiment.

FIG. 2 is a cross-sectional view showing a step of forming an n-type diffusion layer of the heat-sensitive portion according to the first embodiment.

FIG. 3 is a cross-sectional view showing a step of separating the heat-sensitive portion in the first embodiment.

FIG. 4 is a diagram showing a voltage applying mechanism and a current detecting mechanism for the pn junction of the heat-sensitive section in the first embodiment.

FIG. 5 is a diagram showing a main configuration of a semiconductor infrared imaging device according to a second embodiment.

FIG. 6 is a cross-sectional view showing the configuration of a heat-sensitive part of a semiconductor infrared imaging device according to a third embodiment.

7A and 7B are a plan view and a cross-sectional view showing a configuration of a heat-sensitive part of a semiconductor infrared imaging device according to a fourth embodiment.

FIG. 8 is a diagram showing a circuit configuration of a semiconductor infrared imaging device according to a fifth embodiment.

FIG. 9 is a diagram showing a circuit configuration of a semiconductor infrared imaging device according to a sixth embodiment.

FIG. 10 is a diagram showing a circuit configuration of a semiconductor infrared imaging device according to a sixth embodiment.

FIG. 11 is a diagram showing a circuit configuration of a semiconductor infrared detection device according to a seventh embodiment.

FIG. 12 is a plan view and a sectional view showing an example of a conventional semiconductor infrared detection element.

[Explanation of symbols]

10 ... SOI substrate 11 ... Si substrate 12 ... SiO ₂ film 13 ... P-type Si layer (SOI layer) 14, 74 ... N-type diffusion layer 15 ... Insulating film 16 ... P-side electrode 17 ... N-side electrodes 18, 19 ... Wiring 20 ... Heat-sensitive parts 21, 22 ... Support legs 25, 26 Mask 30 ... Hollow structure parts 31, 32 ... Address line 41 ... Variable voltage source 42 ... Current detector 71 ... Element isolation oxide film

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 27/14 G01J 1/02

Claims (6)

(57) [Claims] 1. A heat-sensitive part including a pn-junction part, which is formed by laminating on a semiconductor layer on an insulator and has a joint surface formed in an uneven shape, except that at least one support leg surrounds the heat-sensitive part. It is configured to be thermally separated from the semiconductor substrate by a hollow structure, a forward bias voltage is applied to the pn junction, and a current flowing in the pn junction that changes according to the temperature of the heat sensitive portion is detected. A stack pn junction type semiconductor infrared detecting element, which detects infrared rays based on a change in detected current. 2. The semiconductor infrared detecting element according to claim 1, wherein the cross-sectional shape of the pn junction surface of the pn junction changes periodically. 3. The semiconductor infrared detecting element according to claim 1, wherein the change of the pn junction surface of the pn junction is a lattice shape when viewed from the surface direction of the semiconductor layer. 4. A pn junction having a junction surface formed in a laminated manner on a semiconductor layer on an insulator and having an irregular joint surface, and at least one supporting leg contacts the periphery including the pn junction. In addition to the above, a heat-sensitive portion thermally separated from a semiconductor substrate by a hollow structure, voltage applying means for applying a forward bias voltage to the pn junction portion, and the pn junction portion that changes according to the temperature of the heat-sensitive portion. A stack pn junction type semiconductor infrared detecting device comprising: a current detecting means for detecting a current flowing through the infrared ray detecting means, and detecting infrared rays based on a change in a current detected by the current detecting means. 5. A pn junction which is formed by laminating on a semiconductor layer on an insulator and has a joint surface formed in an uneven shape, and a pn junction including the pn junction, the periphery of which is contacted by at least one supporting leg. In addition to the above, a heat-sensitive portion thermally separated from the semiconductor substrate by the hollow structure, a heat-sensitive portion array in which a plurality of heat-sensitive portions are two-dimensionally arranged, and a forward bias voltage are applied to the pn junction of each heat-sensitive portion. And a current detecting unit that detects a current flowing through the pn junction that changes according to the temperature of each of the heat-sensitive units. Based on a change in the current detected by the current detecting unit. A stack pn junction type semiconductor infrared imaging device, characterized by picking up an infrared image by means of a semiconductor device. 6. A heat-sensitive portion including a pn junction formed by laminating on a semiconductor layer on an insulator and thermally separated from a semiconductor substrate, and a forward bias voltage is applied to the pn junction. In a method of manufacturing a stacked pn junction type semiconductor infrared detecting element which is used for detecting infrared rays by detecting a current that flows sometimes, a predetermined mask is formed on a semiconductor layer formed on a semiconductor substrate via an insulating film. The step of forming a pn junction having an uneven joint surface by ion implantation and diffusion using the same and the heat-sensitive part including the pn junction contacting the periphery with at least one supporting leg A semiconductor infrared detector comprising: a step of selectively etching a semiconductor layer and an insulating film around the heat-sensitive part and a substrate below the heat-sensitive part so as to be thermally separated from the substrate. Method for manufacturing output device.