JPH11274553A - Infrared radiation element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the mechanical strength compatible with the electric characteristics and radiation characteristics. SOLUTION: An n<-> type Si element substrate 21 has a through-hole 22, a strip-like p-type semiconductor diaphragm 23 is formed so as to close one opening face of the hole 22, and first and second metal electrodes 25, 26 are provided on both end faces of the diaphragm 23. When a voltage is applied to the first and second electrodes 25, 26, a current flows in the diaphragm 23 to heat the diaphragm 23 and radiate infrared rays. One surface 21a of the element substrate 21 and surface of the diaphragm 23 are covered with an Si oxide film for accelerating the infrared radiation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared radiating element having a diaphragm structure for radiating infrared rays from a diaphragm formed on an element substrate such as silicon.

[0002]

2. Description of the Related Art In addition to being used as a light emitting element, an infrared emitting element is also used as a light source of a gas analyzer utilizing infrared absorption.

[0003] The infrared light source conventionally used for the infrared gas analysis is a light source in which a heater is embedded in ceramic or a material in which a platinum or tungsten filament is sealed in a glass tube. In addition, there is a problem that the change with time is large, and a high-speed mechanical chopper is required when intermittently emitting infrared rays (chopping) due to a large heat capacity.

In order to solve this problem, a so-called microbridge structure is provided in which a bridge portion made of a semiconductor is provided on one surface of an element substrate such as silicon by using micromachining technology, and the bridge portion is energized to emit infrared rays. Various infrared radiation elements have been proposed.

As an infrared radiating element having a microbridge structure, one having a structure shown in FIGS. 23 and 24 is known.

The infrared radiating element 10 is formed on one side 1 of a silicon element substrate 11 by micromachining technology.
A bridge portion 12 made of a p-type semiconductor is provided on the side of 1a, first and second electrodes 14 and 15 are provided at both ends of the bridge portion 12, and a depression 16 is provided at the center of one surface of the element substrate 11 to form the bridge portion 12. A heat separation space 17 is formed between the lower surface and the element substrate. Note that portions of the electrodes 14 and 15 except for the surfaces are covered with a protective thin film 18.

In this infrared radiation element 10, the electrodes 14,
When a voltage is applied between the bridge portions 15, a bridge portion 1 made of a p-type semiconductor is formed.
Electricity flows through the bridge 2 to generate heat in the bridge portion 12 and radiate infrared rays.

The infrared radiation element having such a microbridge structure has an advantage that high-speed chopping can be performed since the element shape is small and the heat capacity is small.

[0009]

However, when the width and thickness of the bridge portion 12 are increased in the infrared radiating element 10 having the above-described microbridge structure in order to make the bridge structure more robust, the resistance value of the bridge portion itself becomes smaller. As a result, there is a problem that the drive current becomes excessively large, making it difficult to use.

In order to set the drive current to an appropriate value,
If the width or thickness of the bridge portion 12 is reduced, the mechanical strength of the bridge portion is significantly reduced, and the bridge portion 12 is destroyed by fatigue caused by a sudden shape change due to external force or current on / off. In addition, since the area of the bridge is reduced, the amount of infrared radiation is also reduced.

An object of the present invention is to solve these problems and to provide an infrared radiating element having both mechanical strength and electrical and radiation characteristics.

[0012]

According to a first aspect of the present invention, there is provided an infrared radiation device comprising: an element substrate having a hole penetrating from one surface side to an opposite surface; A diaphragm portion made of a p-type semiconductor which is formed so as to close one opening surface of the hole and emits infrared rays when energized; first and second electrodes provided at both ends of the diaphragm portion; An infrared radiation promoting film formed to cover at least one surface of the diaphragm.

The infrared radiation element according to claim 2 of the present invention is the infrared radiation element according to claim 1, wherein the infrared radiation promoting film is formed so as to cover both surfaces of the diaphragm.
On the opposite side of the element substrate, there is provided a reflecting portion that closes the other opening surface of the hole and reflects the infrared radiation radiated from the diaphragm toward the diaphragm.

According to a third aspect of the present invention, in the infrared radiating element according to the first or second aspect, the element substrate is provided with a plurality of pairs of the hole and the diaphragm. A plurality of diaphragm parts are electrically connected.

According to a fourth aspect of the present invention, there is provided an infrared radiating element having an element substrate having a hole penetrating from one surface side to an opposite surface, and one opening surface of the hole being closed on one surface side of the element substrate. A formed diaphragm made of a p-type semiconductor, a heating part provided on at least one surface side of the diaphragm and made of an n-type semiconductor that receives an electric current and emits infrared rays, and a first part provided on both ends of the heating part. , A second electrode, and an infrared radiation promoting film formed to cover the surface of the heat generating portion.

According to a fifth aspect of the present invention, there is provided the infrared radiating element according to the fourth aspect, wherein a third electrode is provided on the diaphragm.

According to a sixth aspect of the present invention, in the infrared radiating element according to the fourth or fifth aspect, the heat generating portion is configured such that a width at a central portion is larger than a width at both ends. Is formed.

According to a seventh aspect of the present invention, in the infrared radiating element according to the fourth, fifth or sixth aspect, the hole, the diaphragm and the heat generating portion are formed on the element substrate. A plurality of sets are provided, and the plurality of heat generating units are electrically connected.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. In the following description of each embodiment, the same components will be denoted by the same reference numerals and description thereof will be omitted.

(First Embodiment) FIGS. 1 and 2 show an infrared radiation element 20 according to a first embodiment of the present invention. The element substrate 21 of the infrared radiating element 20 is made of n ⁻ -type silicon.
A hole 22 penetrating in a trapezoidal shape is provided on the side.

On one side 21a of the element substrate 21, a band-shaped diaphragm portion 23 made of a p-type semiconductor is formed so as to cover one opening surface of the hole 22. First and second electrodes 25 and 26 made of a metal material are provided on both end surfaces of the diaphragm portion 23. When a voltage is applied to the first and second electrodes 25 and 26, the diaphragm portion 23 When electricity flows, the diaphragm 23 generates heat and emits infrared rays.

As shown in FIG. 2, not only the surface protection but also a silicon oxide film 27 for promoting the emission of infrared rays is provided on the one surface 21a side of the element substrate 21 and the surface of the diaphragm portion 23. The film 27 is covered, and the emission of infrared rays from the diaphragm 23 is promoted by the film 27.

That is, in the case of only protecting the element surface, the thickness of the oxide film is generally about 0.1 μm.
As shown in FIG. 3, it has been found that when the thickness of the silicon oxide film is set to a certain value (approximately 1 μm) or more, the emissivity of infrared rays is significantly increased. Therefore, in the infrared radiation element 20 of this embodiment, at least the diaphragm The thickness of the silicon oxide film 27 on the surface of the portion 23 is set to 0.4 μm or more (for example, about 1 μm).

In the infrared radiating element 20 in which the electrodes are provided on the diaphragm having a so-called diaphragm structure, the structure itself is more robust than the infrared radiating element having a microbridge structure. And the radiation power density of infrared rays can be greatly increased. In addition, since the heat of the diaphragm 23 is appropriately radiated through the diaphragm structure, the chopping frequency does not need to be reduced, and high-speed modulation can be performed.

This infrared radiation element 20 can be easily manufactured by micromachining technology. Hereinafter, the manufacturing method will be briefly described.

First, an n ⁻ -type single crystal semiconductor having a specific resistance of 8 to 15 Ω · cm and a plane orientation of (100) is prepared as an element substrate, and one surface of the element substrate is subjected to a thermal oxidation treatment to obtain a 0.7 μm A thermal oxide film having a thickness is formed, and the thermal oxide film in a region where the p-type semiconductor layer is to be formed is removed by photolithography.

Next, one surface of the element substrate is ion-implanted at a high concentration, for example, at a dose of 4.0 × 1.
0 ¹⁶ ions / cm ² of boron are implanted at an acceleration voltage of 175 kV, and annealing is performed in a high-temperature nitrogen gas atmosphere of 1100 ° C. to 1200 ° C. for about 10 minutes to 60 minutes to form a region where the oxide film is removed. After a p-type semiconductor layer having a desired thickness (for example, 5 μm) is formed as the diaphragm 23, the thermal oxide film on the surface of the element substrate is removed.

Next, a thermal oxide film is formed on one surface of the element substrate by thermal oxidation to a thickness of about 0.4 μm to 1 μm (this oxide film is for protecting the element surface and promoting infrared radiation). Then, the thermal oxide film in the electrode formation region at both ends of the diaphragm portion 23 is removed by photolithography, and a thin film of gold, aluminum, or the like is formed on the entire surface of the element substrate by a vacuum deposition method, and then, by patterning, other than the electrode formation region. By removing the thin film, first and second electrodes 25 and 26 are formed.

Finally, a hole 22 penetrating from the lower surface of the diaphragm 23 to the opposite surface of the element substrate is formed by utilizing the anisotropic etching characteristics of an ammonia solution or the like and the carrier concentration dependence of the etching rate.

The infrared radiating element thus formed is divided into chips by a dicer, mounted on a package such as a TO5 type, and the terminals of the package and the first and second electrodes 25 and 26 of the infrared radiating element are connected. The space is wired.
At the time of this mounting, the inside of the package is hermetically sealed with an inert gas atmosphere depending on the use. Glass, sapphire, calcium fluoride, or the like is used for the infrared radiation window of the package.

As described above, in the infrared radiator in which the infrared radiating element is mounted in the package, when a voltage is applied between the terminals, electricity flows to the heat generating portion of the internal infrared radiating element to radiate infrared rays. Infrared light is output from the window.

(Second Embodiment) FIGS. 4 and 5 show an infrared radiation element 30 according to a second embodiment of the present invention. The infrared radiating element 30 has a silicon oxide film 27 having a thickness of about 0.4 to 1.0 μm
Is provided, and a reflecting portion 38 made of a metal material that reflects the infrared rays toward the diaphragm portion 23 is provided on the opposite surface side of the element substrate 21 while promoting the emission of the infrared rays in the direction of the hole 22.
The infrared rays radiated from both surfaces of the diaphragm portion 23 are
And the radiated power density is further increased.

(Third Embodiment) FIGS. 6 and 7 show an infrared radiating element 40 according to a third embodiment of the present invention. This infrared radiation element 40 is provided with a plurality of diaphragms per element. That is, a square rod-shaped element substrate 4 made of silicon
A plurality of holes 42 _{1 to} 42 _N are provided in a line at regular intervals in one,
The plurality of N holes 42 _{1 to} 42 _N are connected to one surface 41 a of the element substrate.
And a metal thin film 45 _{1 to} 45 _{N + 1} is formed at a position where the p-type semiconductor layer 43 is equally divided into a plurality of N and at both ends thereof. Is covered with an oxide film 47 for protection and promotion of infrared radiation.

With such a configuration, N p-type semiconductor layers 43 ₁ to 43 _N are formed in tandem on _one p-type semiconductor layer 43, and the p-type semiconductor layers 43 ₁ to 43 _n are formed of the metal thin film 45 _2. ~
45 _N connected in series.

Here, for example, the metal thin films 45 _{1 at} both ends,
The 45 N + ₁ first of the element, when a voltage is applied between the electrodes and the second electrodes, a current flows through the respective diaphragm portions 43 ₁ ~ 43 _N, infrared from the diaphragm portions 43 ₁ ~ 43 _N Radiated.

When N is an even number, for example, the metal thin films 45 ₁ and 45 _{N + 1 at} both ends are connected by a pattern or another wiring material, and _{one of} the metal thin films 45 ₁ and 45 _{N + 1} is connected. , An intermediate metal thin film 45 _{N / 2 + 1} may be applied to emit infrared light. In this case, N / 2 diaphragm units connected in series are driven in parallel.

Although not shown, it is also possible to form a single infrared radiation element by arranging a plurality of diaphragms vertically and horizontally and connecting them in series or in parallel.

As described above, the infrared radiating element in which a plurality of diaphragms are provided for each element and the diaphragms are connected by wiring on the element can increase the radiation power of infrared rays by the number of the diaphragms. It can be used as a component of a heater, and can be manufactured inexpensively by the same process as in the past.

(Fourth Embodiment) FIGS. 8 and 9 show an infrared radiation element 50 according to a fourth embodiment of the present invention. In the infrared radiating element 50, a heat generating portion 54 made of an n-type semiconductor is formed on the surface of the diaphragm portion 23.
The first and second electrodes 55 and 56 are formed at both ends of the surface of the substrate 4.

As described above, the infrared radiating element 50 having the two-layer structure in which the diaphragm 23 is used as a support for the heat generating portion 54 can have a more rigid structure, and further has electrical characteristics and infrared radiation characteristics. Can be arbitrarily set independently of the shape of the diaphragm portion 23.

In the case where the heat generating portion 55 made of an n-type semiconductor is provided on the surface of the diaphragm portion 23 as described above, after the diaphragm portion 23 is formed, one side of the element substrate is subjected to thermal oxidation treatment by thermal oxidation.
After forming a thermal oxide film with a thickness of about 5 μm and removing the thermal oxide film in a region where an n-type semiconductor is to be formed by photolithography, one surface of the element substrate is ion-implanted.
High concentration, for example, 4.0 × 10 ¹⁶ ions /
cm ² of phosphorus or arsenic is implanted at an accelerating voltage of about 125 kV, and annealing is performed in a high-temperature nitrogen gas atmosphere of, for example, 1100 ° C. to 1200 ° C. for about 10 to 30 minutes. The desired thickness (0.
An n-type semiconductor layer (5 μm to 5 μm) is formed as the heat generating portion 54. Then, after removing the thermal oxide film on the surface, the first and second electrodes 55 and 56 are formed.

The thickness of the diaphragm 23 is, for example, 5 mm when the length of the diaphragm 23 is about 1 mm and the width is about 0.5 mm.
μm is necessary and sufficient strength, and the length of the diaphragm 23 is 5 m
When m and the width are about 3 mm, the strength is required and sufficient at 10 μm.

The thickness of the n-type semiconductor of the heat generating portion 54 is
It can be arbitrarily set in the range of 0.5 μm to 5 μm depending on the ion implantation amount, the annealing temperature, and the annealing time. For example, the ion implantation amount of phosphorus is 2 × 10 ¹⁶
If the ion / cm ² , the implantation voltage is 125 kV, the annealing temperature is 1180 ° C., and the annealing time is 30 minutes,
An n-type semiconductor having a carrier concentration of 4 × 10 ²⁰ cm ⁻³ and a thickness of 0.5 μm can be formed on the surface of the p-type semiconductor of the diaphragm portion 23, and the width of the n-type semiconductor can be adjusted so that the resistance value of the heating portion can be arbitrarily set And the drive current can be set to an appropriate size that is easy to handle.

As described above, the heating section 5 is independently provided on the diaphragm section 23.
The infrared radiating element 50 provided with 4 was able to increase the radiation power density by about 50 times compared to the conventional element without sacrificing the chopping speed.

(Fifth Embodiment) FIG. 10 and FIG.
14 shows an infrared radiating element 60 according to a fifth embodiment of the present invention. The infrared radiating element 60 has a two-layer structure in which the heating part 54 is provided on the diaphragm part 63.
Is provided with a third electrode 69. By applying a reverse bias voltage to the heat generating portion 54 to the third electrode 69 provided on the diaphragm portion 63, it is possible to prevent a current from flowing from the heat generating portion 54 to the diaphragm portion 63. Also, the third
By varying the voltage applied to the electrodes 69, the magnitude of the current flowing through the heat generating portion 54 can be controlled,
The infrared radiation power density can be variably controlled.

(Sixth and Seventh Embodiments) FIGS. 12 to 1
Reference numeral 5 denotes infrared radiation elements 70 and 80 according to the sixth and seventh embodiments of the present invention.

In these infrared radiation elements 70 and 80,
The width of the central portion 74a, 84a of each heat generating portion 74, 84 is widened, and the width of both end portions 74b, 74c, 84b, 84c is set narrow, so that the region of the high temperature portion of the heat generating portion 74, 84 is widened. The radiation density of infrared rays is further increased.

FIG. 16 shows the radiation distribution characteristic P of the infrared radiation element 50 of the fourth embodiment and the infrared radiation in which the width of the central portion of the heat generating portion is set to be larger than the width of both ends as described above. The radiation distribution characteristics Q of the radiating elements 70 and 80 are shown. As is apparent from FIG. 16, the radiation distribution characteristic P of the infrared radiating element 50 in which the width of the heat generating portion is set to be uniform is a single peak characteristic in which the temperature is maximum at the center of the heat generating portion, whereas the infrared radiation The radiation characteristics Q of the elements 70 and 80 are trapezoidal characteristics in which a high-temperature portion covers a wide range.

In the infrared radiating elements 70 and 80 having such a radiation characteristic Q, since the area of the high temperature part is large, a higher radiation power density can be obtained.

(Eighth Embodiment) FIG. 17 and FIG.
14 shows an infrared radiating element 90 according to an eighth embodiment of the present invention. The infrared radiating element 90 has a structure in which the infrared radiating elements of the fourth embodiment are connected in tandem.

That is, a plurality of holes 92 _{1 to} 92 _N are provided in a row at regular intervals in a silicon rod-shaped element substrate 91, and the plurality of N holes 92 _{1 to} 92 _N are formed on one surface 91 a of the element substrate. It is closed with one long p-type semiconductor layer 93, and one long n-type semiconductor layer 94 is formed on the surface thereof.
5 _{1 to} 95 _{N + 1} are formed, and the surface of the element substrate 91 is covered with an oxide film 97 for protection and promotion of infrared radiation.

With such a configuration, N partition portions 93 _{1 to} 93 _N are formed in tandem on _one p-type semiconductor layer 93, and a metal thin film is formed on one n-type semiconductor layer 94. 95 _2
N heat generating portions 94 ₁ connected in series by ~ 95 _N
~ 94 _N has been formed.

Here, for example, the metal thin films 95 _{1 at} both ends,
The first of the elements 95 N + _1, when a voltage is applied between the electrodes and the second electrodes, a current flows through the respective heating portions 94 ₁ to 94 _N, the infrared from the heating unit 94 ₁ to 94 _N Radiated.

Although not shown, it is also possible to form a single infrared radiation element by arranging a plurality of heat generating parts vertically and horizontally and connecting them in series or in parallel.

As described above, the infrared radiating element in which a plurality of heat generating parts are provided for each element and the heat generating parts are connected by wiring on the element can increase the radiation power of infrared rays by the number of the heat generating parts. It can be used as a component of a heater, and can be manufactured inexpensively by the same process as in the past.

In each of the above embodiments, the diaphragm completely covers the hole of the element substrate, but this does not limit the present invention. For example, as in an infrared radiating element 100 shown in FIGS.
Is made smaller than the upper width of the hole 22 (or the upper width of the hole 22 is made larger than the width of the strip-shaped diaphragm portion),
The upper side of the hole 22 may be opened on both sides of 3 '. In this case, the diaphragm structure can be reinforced by extending the projections 23b and 23d on the element substrate from both sides of the central portion 23a of the diaphragm 23 '. In this case, even if the lower part of the hole 22 is closed at the time of mounting the element, heat in the hole 22 can be released, which is advantageous in terms of heat radiation. This method can be applied to all the embodiments described above.

The infrared radiation element 11 shown in FIGS.
If the surface of the lower surface 21b of the element substrate 21 is covered with a metal thin film 28 of, for example, nickel-laurenium (Nilr) or gold (Au), as shown in FIG. Becomes easier. This method of covering the lower surface side of the element substrate with the metal thin film 28 can be applied to all the embodiments described above.

A third electrode may be provided on the diaphragm 23 of the infrared radiating elements 70 and 80 shown in FIGS. 12 to 15, and the infrared radiating element 90 shown in FIGS.
Of the heat generating portions 94 _{1 to} 94 _N of the infrared radiating elements 70 and 80
Or a third electrode may be provided on the n-type semiconductor layer 93 of the infrared radiation element 90 shown in FIGS.

[0059]

As described above, according to the first aspect of the present invention,
The infrared radiating element has a structure in which an electrode is provided on the diaphragm of a so-called diaphragm structure and emits infrared rays from the diaphragm. And the radiation power density of infrared rays can be greatly increased. In addition, since the heat of the diaphragm portion is appropriately radiated through the diaphragm structure, the chopping frequency does not need to be reduced, and high-speed modulation can be performed.

In the infrared radiating element according to the second aspect of the present invention, a film for promoting the emission of infrared rays is provided on both surfaces of the diaphragm, and a reflecting portion is provided on the opposite surface of the element substrate. Infrared rays radiated from the substrate can be radiated intensively to one surface side of the element substrate, and the radiation power density can be further increased.

In the infrared radiating element according to the third aspect of the present invention, a plurality of pairs of holes and diaphragms are provided on the element substrate and the plurality of diaphragms are electrically connected. Infrared rays can be emitted with high power and can be used as various heaters.

Further, the infrared radiating element according to claim 4 of the present invention has a two-layer structure in which a heat generating portion is formed by an n-type semiconductor on the surface of a p-type semiconductor forming a diaphragm portion, and is provided at both ends of the heat generating portion. Since the first and second electrodes have a structure that emits infrared rays by applying a voltage to the first and second electrodes, the structure can be made even more rigid, and a heating section can be formed independently of the shape of the diaphragm section. Large power infrared rays can be emitted with an appropriate drive current.

In the infrared radiating element according to the fifth aspect of the present invention, since the third electrode is provided on the diaphragm supporting the heating section, it is possible to prevent the current from flowing from the heating section to the diaphragm.
The amount of infrared radiation can be variably controlled.

In the infrared radiating element according to claim 6 of the present invention, since the width of the central portion of the heat generating portion is formed to be larger than the width of both ends, the high temperature region of the heat generating portion is widened,
The emissivity of infrared rays can be further increased.

In the infrared radiating element according to the seventh aspect of the present invention, a plurality of sets of diaphragms and heat generating parts are provided on one surface of the element substrate, and the plurality of heat generating parts are electrically connected. It can be radiated by power and can be applied to heaters and the like.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line BB of FIG. 1;

FIG. 3 is a diagram showing the relationship between the thickness of an oxide film and infrared emissivity.

FIG. 4 is a plan view of a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line CC of FIG. 4;

FIG. 6 is a plan view of a third embodiment of the present invention.

FIG. 7 is a sectional view taken along line DD of FIG. 6;

FIG. 8 is a plan view of a fourth embodiment of the present invention.

FIG. 9 is a sectional view taken along line EE of FIG. 8;

FIG. 10 is a plan view of a fifth embodiment of the present invention.

11 is a sectional view taken along line FF of FIG. 10;

FIG. 12 is a plan view of a sixth embodiment of the present invention.

13 is a sectional view taken along line GG of FIG.

FIG. 14 is a plan view of a seventh embodiment of the present invention.

FIG. 15 is a sectional view taken along line HH of FIG. 14;

FIG. 16 is a characteristic diagram showing a radiation distribution according to the embodiment.

FIG. 17 is a plan view of an eighth embodiment of the present invention.

18 is a sectional view taken along line II of FIG. 17;

FIG. 19 is a plan view of a ninth embodiment of the present invention.

20 is a sectional view taken along line JJ of FIG. 19;

FIG. 21 is a plan view of a tenth embodiment of the present invention.

FIG. 22 is a sectional view taken along the line KK of FIG. 21;

FIG. 23 is a plan view of a conventional element.

24 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

20, 30, 40, 50, 60, 70, 80, 90 1
00, 110 Infrared radiating element 21, 41, 91 Element substrate 22, 42 _{1 to} 42 _N , 92 _{1 to} 92 _N Hole 23, 43 ₁ to 43 _N , 73, 83, 93 _{1 to} 93 _N
Diaphragm part 25, 45 ₁ , 55, 95 ₁ first electrode 26, 45 _{N + 1} , 56, 95 _{N + 1} second electrode 27, 47, 97 silicon oxide film 28 metal thin film 38 reflecting part 54, 74, 84, 94 _{1 to} 94 _N Heating part 69 Third electrode

Claims (7)

[Claims] 1. An element substrate having a hole penetrating from one surface side to an opposite surface, and an element substrate formed so as to close one opening surface of the hole on one surface side of the element substrate, and receiving an electric current to emit infrared rays. Infrared radiating element comprising: a diaphragm portion made of a type semiconductor; first and second electrodes provided at both ends of the diaphragm portion; and an infrared radiation promoting film formed to cover at least one surface of the diaphragm portion. . 2. The infrared radiation promoting film is formed so as to cover both surfaces of the diaphragm portion, and the other opening side of the hole is radiated from the diaphragm portion on the opposite side of the element substrate to the other opening surface of the hole. 2. The infrared radiating element according to claim 1, further comprising a reflecting portion for reflecting infrared light toward the diaphragm. 3. The element substrate according to claim 1, wherein a plurality of pairs of the holes and the diaphragm are provided in the element substrate, and the plurality of diaphragms are electrically connected. Infrared radiating element. 4. An element substrate having a hole penetrating from one surface side to an opposite surface; a diaphragm portion made of a p-type semiconductor formed to cover one opening surface of the hole on one surface side of the element substrate; A heat-generating portion provided on at least one surface side of the diaphragm portion and made of an n-type semiconductor that receives an electric current and emits infrared rays; first and second electrodes provided on both ends of the heat-generating portion; An infrared radiating element comprising: an infrared radiation promoting film formed so as to cover the surface. 5. An infrared radiating element according to claim 4, wherein a third electrode is provided on said diaphragm. 6. The infrared radiating element according to claim 4, wherein said heat generating portion is formed such that a width at a center portion is larger than a width at both end portions. 7. The element substrate according to claim 4, wherein a plurality of sets of the holes, the diaphragm, and the heat generating portion are provided, and the plurality of heat generating portions are electrically connected. The infrared radiation element according to claim 5 or 6.