JP2011060953A - Optical sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sensor which has suppressed power consumption during use without having a larger size in a horizontal direction of a substrate. <P>SOLUTION: The optical sensor includes the substrate 11, a first electrode layer 13 laminated on the substrate 11, a first oxide semiconductor layer 14 laminated on a partial region on the first electrode layer 13, and a second electrode layer 15 laminated on the first oxide semiconductor layer 14. At least a part of an outer periphery 13A of the first electrode 13 or an outer periphery 15A of the second electrode 15 that cuts off incident light overlaps the second electrode layer 15 or first electrode layer 13 with the first oxide semiconductor layer 14 interposed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical sensor that detects light including ultraviolet rays, and more particularly to an optical sensor that detects light using an oxide semiconductor layer stacked on a substrate.

  A conventional optical sensor for detecting ultraviolet rays uses an ultraviolet photoelectric tube in a portion that receives ultraviolet rays. However, since the ultraviolet phototube requires a very high driving voltage, a structure for ensuring insulation is required, and there is a problem that the photosensor itself is enlarged. In recent years, many optical sensors using solid elements have been developed in order to solve such problems.

  For example, Patent Document 1 discloses an optical sensor in which a diamond film is stacked on a substrate, and a pair of first and second electrodes are stacked on the diamond film. The optical sensor disclosed in Patent Document 1 applies a direct current voltage between a first electrode and a second electrode, and a current caused by movement of electrons and holes in the diamond film caused by ultraviolet light entering the diamond film. Measures and detects ultraviolet rays.

Japanese Patent No. 3560462

  Since the optical sensor disclosed in Patent Document 1 measures the current flowing between the first electrode and the second electrode through the diamond film and detects ultraviolet rays, the first electrode and the second electrode The resistance value between the first electrode and the second electrode can be adjusted by changing the distance between the first electrode and the second electrode. When the resistance value between the first electrode and the second electrode is increased, the current flowing between the first electrode and the second electrode is reduced, so that power consumption during use can be suppressed. However, in the optical sensor disclosed in Patent Document 1, in order to increase the resistance value between the first electrode and the second electrode, it is necessary to increase the distance between the first electrode and the second electrode. There is a problem that the size of the optical sensor increases in the horizontal direction of the substrate. Increasing the size of the optical sensor in the horizontal direction of the substrate causes problems such as a reduction in the number of optical sensors obtained from a single wafer and an increase in the area of the optical sensor in a circuit board to be mounted.

  In addition, in the optical sensor disclosed in Patent Document 1, when the distance between the first electrode and the second electrode is increased in order to increase the resistance value between the first electrode and the second electrode, Since the electric field between the 1st electrode and the 2nd electrode becomes weak, there was a problem that the responsiveness of an optical sensor became low.

  Furthermore, in the optical sensor disclosed in FIG. 4 of Patent Document 1, when the diamond film is thinned, the current leaks to the metal film on the substrate as compared with the current flowing between the first electrode and the second electrode. Increases, and the sensitivity of the optical sensor decreases. Therefore, there has been a problem that the diamond film cannot be thinned to reduce the manufacturing cost.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical sensor capable of suppressing power consumption during use without increasing the size of the optical sensor with respect to the horizontal direction of the substrate. And

  In order to achieve the above object, an optical sensor according to a first invention includes a substrate, a first electrode layer laminated on the substrate, and a first electrode layer laminated on a part of the region on the first electrode layer. 1 oxide semiconductor layer, and 2nd electrode layer laminated | stacked on this 1st oxide semiconductor layer, At least one part of the outer periphery of the said 1st electrode layer or the said 2nd electrode layer which interrupts incident light Is overlapped with the second electrode layer or the first electrode layer with the first oxide semiconductor layer interposed therebetween.

  According to a second aspect of the present invention, there is provided an optical sensor according to the first aspect, further comprising a third electrode layer laminated in a region on the first electrode layer different from a region where the first oxide semiconductor layer is laminated. .

  An optical sensor according to a third invention is the optical sensor according to the first or second invention, wherein the optical sensor is electrically connected to the first oxide semiconductor layer through the first electrode layer, and the third electrode layer and the first electrode are electrically connected. A second oxide semiconductor layer stacked between the electrode layer and at least a part of an outer periphery of the first electrode layer or the third electrode layer that blocks incident light; And the third electrode layer or the first electrode layer.

  An optical sensor according to a fourth invention is the optical sensor according to the third invention, wherein the second oxide semiconductor layer is a ZnO film.

In the optical sensor according to a fifth aspect of the present invention based on the third aspect, the second oxide semiconductor layer is a (Ba, Sr) TiO ₃ film.

An optical sensor according to a sixth aspect of the present invention is the optical sensor according to the third aspect, wherein the second oxide semiconductor layer is a Cu ₂ O film.

  The optical sensor according to a seventh aspect is the optical sensor according to any one of the first to sixth aspects, wherein the first oxide semiconductor layer is a ZnO film.

An optical sensor according to an eighth aspect of the present invention is the optical sensor according to any one of the first to sixth aspects, wherein the first oxide semiconductor layer is a (Ba, Sr) TiO ₃ film.

The optical sensor according to a ninth aspect of the present invention is the optical sensor according to any one of the first to sixth aspects, wherein the first oxide semiconductor layer is a Cu ₂ O film.

  In the optical sensor according to a tenth aspect, in the third aspect, the material of the second oxide semiconductor layer is different from the material of the first oxide semiconductor layer.

  An optical sensor according to an eleventh aspect of the present invention is the optical sensor according to any one of the first to tenth aspects, wherein the first electrode layer or the second electrode layer that blocks incident light is the first electrode layer or the first electrode layer. Compared with the case where the shape of the two-electrode layer is rectangular, the outer circumference of the first electrode layer or the second electrode layer is longer.

  An optical sensor according to a twelfth aspect of the present invention is the optical sensor according to any one of the first to eleventh aspects, wherein the first electrode layer or the third electrode layer that blocks incident light is the first electrode layer or the first electrode layer. Compared to the case where the shape of the three-electrode layer is rectangular, the outer periphery of the first electrode layer or the third electrode layer is longer.

  An optical sensor according to a thirteenth aspect of the present invention is the optical sensor according to any one of the first to twelfth aspects, wherein the substrate is made of a material that transmits light.

  In the first invention, the first electrode layer, the first oxide semiconductor layer, and the second electrode layer are laminated on the substrate, and at least one of the outer circumferences of the first electrode layer or the second electrode layer that blocks incident light. Since the portion overlaps the second electrode layer or the first electrode layer through the first oxide semiconductor layer, light is detected by a change in the current value between the second electrode layer and the first electrode layer. can do. In order to reduce power consumption during use, it is preferable to increase the resistance value between the second electrode layer and the first electrode layer, but the resistance value between the second electrode layer and the first electrode layer is preferred. Even when the thickness of the first oxide semiconductor layer is increased to increase the thickness of the first sensor, the size of the photosensor does not increase with respect to the horizontal direction of the substrate.

  In the second invention, since the third electrode layer is laminated in a region on the first electrode layer different from the region in which the first oxide semiconductor layer is laminated, the second electrode layer and the second electrode layer on the same side of the substrate Light can be detected by measuring the current value between the three electrode layers.

  According to a third aspect of the invention, a second oxide semiconductor layer is provided that is electrically connected to the first oxide semiconductor layer via the first electrode layer and is laminated between the third electrode layer and the first electrode layer. Since at least a part of the outer periphery of the first electrode layer or the third electrode layer that blocks incident light overlaps the third electrode layer or the first electrode layer with the second oxide semiconductor layer interposed therebetween, Light can be detected even when the current value changes between the three electrode layers and the first electrode layer, and the change in the current value between the second electrode layer and the third electrode layer increases, thereby Sensitivity can be increased.

  In the fourth and seventh inventions, since the first or second oxide semiconductor layer is a ZnO film, light (ultraviolet light) having a wavelength of 380 nm or less can be detected.

In the fifth and eighth inventions, since the first or second oxide semiconductor layer is a (Ba, Sr) TiO ₃ film, light (ultraviolet light) having a wavelength of 290 nm or less can be detected.

In the sixth and ninth inventions, since the first or second oxide semiconductor layer is a Cu ₂ O film, light having a wavelength of 620 nm or less can be detected.

  In the tenth invention, since the material of the second oxide semiconductor layer is different from the material of the first oxide semiconductor layer, an optical sensor having a wide wavelength range of light that can be detected can be realized.

  In the eleventh aspect of the present invention, the first electrode layer or the second electrode layer that blocks the incident light is the first electrode layer or the second electrode layer as compared with the case where the shape of the first electrode layer or the second electrode layer is rectangular. Since the outer periphery of the electrode has a long shape, for example, a comb shape, the number of electron / hole pairs generated by the incidence of light increases, and the change in the current value between the second electrode layer and the third electrode layer increases. Thus, the sensitivity of the optical sensor can be increased.

  In the twelfth invention, the first electrode layer or the third electrode layer that blocks the incident light is the first electrode layer or the third electrode layer as compared with the case where the shape of the first electrode layer or the third electrode layer is rectangular. Since the outer periphery of the electrode has a long shape, for example, a comb shape, the number of electron / hole pairs generated by the incidence of light increases, and the change in the current value between the second electrode layer and the third electrode layer increases. Thus, the sensitivity of the optical sensor can be increased.

  In the thirteenth invention, since the substrate is made of a material that transmits light, it is possible to detect light incident from the substrate side, and the surface that detects light is different from the surface that is connected to the circuit board. When the optical sensor is mounted on the circuit board, the degree of freedom is increased.

  An optical sensor according to the present invention includes a substrate, a first electrode layer stacked on the substrate, a first oxide semiconductor layer stacked on the first electrode layer, and a stack on the first oxide semiconductor layer. And at least part of the outer periphery of the first electrode layer or the second electrode layer that blocks incident light, the second electrode layer or the first electrode via the first oxide semiconductor layer. Since it overlaps with the layer, light can be detected by a change in the current value between the second electrode layer and the first electrode layer. In order to suppress power consumption during use, it is preferable to increase the resistance value between the second electrode layer and the first electrode layer, but the resistance value between the second electrode layer and the first electrode layer is increased. Therefore, even when the thickness of the first oxide semiconductor layer is increased, the size of the photosensor does not increase with respect to the horizontal direction of the substrate. In addition, the number of carriers contained in the first oxide semiconductor layer is reduced and the resistance value between the second electrode layer and the first electrode layer is increased, so that the distance between the second electrode layer and the first electrode layer is increased. The electric field between the second electrode layer and the first electrode layer can be increased by shortening the distance, and the sensitivity of the photosensor can be increased.

It is the schematic which shows the structure of the optical sensor which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the range where the optical sensor which concerns on Embodiment 1 of this invention functions as an optical sensor. It is the schematic which shows the structure of the optical sensor which laminated | stacked the 1st electrode layer, the 1st oxide semiconductor layer, and the 2nd electrode layer on the board | substrate. It is the schematic which shows the structure of the optical sensor which provided the light shielding film in the 15 A outer periphery vicinity of the 2nd electrode layer shown in FIG. FIG. 5 is an exemplary diagram showing a change in current value between the second electrode layer and the first electrode layer of the photosensor shown in FIGS. 3 and 4. It is sectional drawing for demonstrating the manufacturing method of the optical sensor which concerns on Embodiment 1 of this invention. It is the schematic which shows the structure of the optical sensor which concerns on Embodiment 2 of this invention. It is the schematic which shows the structure of the optical sensor which concerns on Embodiment 3 of this invention. It is the schematic which shows the structure of the optical sensor which concerns on Embodiment 4 of this invention.

  Hereinafter, an optical sensor according to an embodiment of the present invention will be specifically described with reference to the drawings. The following embodiments do not limit the invention described in the claims, and all combinations of characteristic items described in the embodiments are essential to the solution. It goes without saying that it is not limited.

(Embodiment 1)
FIG. 1 is a schematic diagram showing the configuration of the photosensor according to Embodiment 1 of the present invention. Fig.1 (a) is a top view which shows the structure of the optical sensor which concerns on Embodiment 1 of this invention. FIG.1 (b) is AA sectional drawing of the optical sensor shown to Fig.1 (a). As shown in FIG. 1B, the optical sensor 1 according to Embodiment 1 of the present invention includes a substrate 11, a first electrode layer 13 stacked on the substrate 11 with an insulating layer 12 interposed therebetween, A first oxide semiconductor layer 14 stacked in a partial region on the first electrode layer 13, a second electrode layer 15 stacked on the first oxide semiconductor layer 14, and a first oxide semiconductor layer; 14 and a third electrode layer 16 laminated in a different region on the first electrode layer 13.

The substrate 11 is a Si substrate, and an insulating layer 12 of a thermal oxide film SiO ₂ is formed so as to cover the substrate 11. The first electrode layer 13 is laminated on the substrate 11 on the surface side on which the insulating layer 12 is formed, and is composed of two layers of a Ti film 13a and a Pt film 13b. The first oxide semiconductor layer 14 is a ZnO film that is stacked in a partial region on the first electrode layer 13 and contains a small amount of carriers. Since the ZnO film has a band gap of 3.3 eV, when used in the optical sensor 1, light (ultraviolet light) having a wavelength of 380 nm or less can be detected.

The second electrode layer 15 is laminated on the first oxide semiconductor layer 14, and is composed of two layers of a Ti film 15a and an Au film 15b. The third electrode layer 16 is laminated in a region on the first electrode layer 13 different from the region where the first oxide semiconductor layer 14 is laminated, and is composed of two layers of a Ti film 16a and an Au film 16b. ing. An insulating layer 17 of the oxide film SiO ₂ is formed so as to cover the first oxide semiconductor layer 14.

  From the opening of the insulating layer 17, the second electrode layer 15 and the third electrode layer 16 are partially exposed to the outside, and the exposed portions of the second electrode layer 15 and the third electrode layer 16 are different from each other. A circuit board (not shown) is connected by wire bonding or the like. When the light sensor 1 is applied with a predetermined voltage between the second electrode layer 15 and the third electrode layer 16 and light is incident from the second electrode layer 15 side, the optical sensor 1 Since the current value between the three electrode layers 16 changes, the light incident from the second electrode layer 15 side can be detected. The optical sensor 1 can also measure the amount of incident light incident from the second electrode layer 15 side from the amount of change in the current value between the second electrode layer 15 and the third electrode layer 16. Since the first electrode layer 13 is electrically connected to the third electrode layer 16, it has the same potential as the third electrode layer 16. Therefore, the current value between the second electrode layer 15 and the third electrode layer 16 can be measured by measuring the current value between the second electrode layer 15 and the first electrode layer 13. A predetermined voltage applied between the second electrode layer 15 and the third electrode layer 16 is supplied from a circuit board (not shown) on which the optical sensor 1 is mounted.

  Next, in the optical sensor 1 according to Embodiment 1 of the present invention, when light is incident from the second electrode layer 15 side, the current value between the second electrode layer 15 and the third electrode layer 16 is The changing principle will be described. FIG. 2 is a schematic diagram showing a range in which the optical sensor 1 according to Embodiment 1 of the present invention functions as an optical sensor. In FIG. 2, a configuration in which the third electrode layer 16 is omitted from the configuration of the photosensor 1 according to the first embodiment is illustrated.

  When a predetermined voltage is applied between the second electrode layer 15 and the first electrode layer 13, an electric field is generated between the second electrode layer 15 and the first electrode layer 13 in the direction indicated by the arrow 20. The electric field generated between the second electrode layer 15 and the first electrode layer 13 is generated in a direction orthogonal to the second electrode layer 15 and the first electrode layer 13. However, in the vicinity of the outer periphery 15 </ b> A of the second electrode layer 15, the electric field generated between the second electrode layer 15 and the first electrode layer 13 is generated in a direction spreading outward from the second electrode layer 15. Therefore, an electric field also exists in the region 21 of the first oxide semiconductor layer 14 near the outer periphery 15A of the second electrode layer 15.

  When light is incident from the second electrode layer 15 side, the first oxide semiconductor layer 14 between the second electrode layer 15 and the first electrode layer 13 is blocked by the second electrode layer 15. Electron / hole pairs are not generated by the photoelectric effect. The first oxide semiconductor layer 14 between the second electrode layer 15 and the first electrode layer 13 has the first electrode layer 15 and the first electrode even when light is incident from the second electrode layer 15 side. The current value between the electrode layer 13 does not change and the optical sensor does not function.

  On the other hand, when light is incident on the region 21 of the first oxide semiconductor layer 14 from the second electrode layer 15 side, there is nothing to block the light, so an electron / hole pair is generated by the photoelectric effect. When an electron / hole pair is generated in the region 21 of the first oxide semiconductor layer 14, electrons and holes are moved by the electric field generated in the region 21, and the region between the second electrode layer 15 and the first electrode layer 13 is moved. The current value changes. That is, the region 21 of the first oxide semiconductor layer 14 functions as an optical sensor.

  Specifically, it indicates that the region 21 of the first oxide semiconductor layer 14 functions as an optical sensor. FIG. 3 is a schematic diagram showing a configuration of the optical sensor 1 in which the first electrode layer 13, the first oxide semiconductor layer 14, and the second electrode layer 15 are stacked on the substrate 11. FIG. 4 is a schematic diagram showing a configuration of the optical sensor 1 in which a light shielding film is provided in the vicinity of the outer periphery 15A of the second electrode layer 15 shown in FIG. In the optical sensor 1 shown in FIG. 3, when light enters from the second electrode layer 15 side, an electron / hole pair is generated in the region 21 of the first oxide semiconductor layer 14. However, in the optical sensor 1 shown in FIG. 4, the light shielding film 41 is provided in the vicinity of the outer periphery 15 </ b> A of the second electrode layer 15 so as to cover the region 21 of the first oxide semiconductor layer 14. Even when light is incident from the side, no light is incident on the region 21 of the first oxide semiconductor layer 14 and no electron-hole pair is generated.

  FIG. 5 is an exemplary diagram showing a change in the current value between the second electrode layer 15 and the first electrode layer 13 of the optical sensor 1 shown in FIGS. 3 and 4. FIG. 5 shows a case where a voltage of 2 V is applied between the second electrode layer 15 and the first electrode layer 13 of the optical sensor 1 shown in FIGS. 3 and 4, and light enters from the second electrode layer 15 side. Current values between the second electrode layer 15 and the first electrode layer 13 when no light is incident from the second electrode layer 15 side are shown.

Specifically, the optical sensor 1 shown in FIG. 3 has 1.5 × 10 ⁻⁶ A between the second electrode layer 15 and the first electrode layer 13 when no light enters from the second electrode layer 15 side. When current flows and light enters from the second electrode layer 15 side, a current of 9.4 × 10 ⁻⁶ A flows between the second electrode layer 15 and the first electrode layer 13. The optical sensor 1 shown in FIG. 3 changes the current value between the second electrode layer 15 and the first electrode layer 13 depending on whether light is incident from the second electrode layer 15 side. Can be detected.

4 has a current of 1.5 × 10 ⁻⁶ A between the second electrode layer 15 and the first electrode layer 13 when no light is incident from the second electrode layer 15 side. When light flows from the second electrode layer 15 side, a current of 1.5 × 10 ⁻⁶ A flows between the second electrode layer 15 and the first electrode layer 13. In the optical sensor 1 shown in FIG. 4, the current value between the second electrode layer 15 and the first electrode layer 13 does not change regardless of whether light is incident from the second electrode layer 15 side. The light cannot be detected.

  Since the optical sensor 1 shown in FIG. 3 has the same configuration as the optical sensor 1 shown in FIG. 4 except that the light shielding film 41 is provided in the vicinity of the outer periphery 15A of the second electrode layer 15, the first oxide semiconductor layer It can be seen that the current value between the second electrode layer 15 and the first electrode layer 13 changes depending on whether light is incident on the 14 regions 21. That is, it can be seen that in the optical sensor 1 shown in FIG. 3, the region 21 of the first oxide semiconductor layer 14 detects light.

  In order for the region 21 to exist in the first oxide semiconductor layer 14, the outer periphery 15A of the second electrode layer 15 is inside the outer periphery 14A of the first oxide semiconductor layer 14, as shown in FIG. Thus, it is necessary to form the second electrode layer 15. In FIG. 1A, in order to clarify the positional relationship between the outer periphery 14A of the first oxide semiconductor layer 14 and the outer periphery 15A of the second electrode layer 15, the first oxide semiconductor layer 14 and the second electrode layer. Illustration of a part of the insulating layer 17 laminated on 15 is omitted.

  Further, as shown in FIG. 1B, the first electrode layer 13 has a first outer periphery 15 </ b> A that overlaps the first electrode layer 13 with the first oxide semiconductor layer 14 interposed therebetween. The oxide semiconductor layer 14 and the second electrode layer 15 are stacked.

Next, a method for manufacturing the optical sensor 1 according to Embodiment 1 of the present invention will be described. FIG. 6 is a cross-sectional view for explaining the method for manufacturing the optical sensor 1 according to the first embodiment of the present invention. A Ti film 13a having a thickness of 50 nm and a Pt film 13b having a thickness of 200 nm are sequentially formed by sputtering on the substrate 11 which is a Si substrate on which the insulating layer 12 of the thermal oxide film SiO ₂ is formed so as to cover the substrate 11. Then, using the photolithography technique and the ion milling and reactive ion etching technique, the Ti film 13a and the Pt film 13b are patterned into a predetermined pattern to form the first electrode layer 13 (FIG. 6A). .

  Next, a ZnO film having a thickness of 500 nm is formed on the first electrode layer 13 by sputtering, and the ZnO film is patterned into a predetermined pattern by using a photolithography technique and a wet etching technique. An oxide semiconductor layer 14 is formed (FIG. 6B). Note that the ZnO film is formed by controlling the oxygen partial pressure during the sputtering process so as to include a small amount of carriers.

  Next, a second electrode layer 15 is formed on the first oxide semiconductor layer 14 by sequentially stacking a Ti film 15a having a thickness of 50 nm and an Au film 15b having a thickness of 1000 nm by a lift-off method, and the first oxide semiconductor layer 14 is formed. A third electrode layer 16 in which a 50 nm thick Ti film 16a and a 1000 nm thick Au film 16b are sequentially stacked is formed by lift-off in a region on the first electrode layer 13 different from the stacked region (FIG. 6C). )). The second electrode layer 15 is formed so that the outer periphery 15A of the second electrode layer 15 overlaps the first electrode layer 13 with the first oxide semiconductor layer 14 interposed therebetween.

Next, a SiO ₂ film having a thickness of 500 nm is formed on the second electrode layer 15 and the third electrode layer 16 by sputtering, and the second electrode layer 15 and the third electrode layer 15 are formed by using a photolithography technique and a wet etching technique. An insulating layer 17 having an opening in which a part of the third electrode layer 16 is exposed to the outside is formed (FIG. 6D).

  As described above, the optical sensor 1 according to Embodiment 1 of the present invention includes the first electrode layer 13, the first oxide semiconductor layer 14, and the second electrode layer 15 that are stacked on the substrate 11, and is incident. Since at least a part of the outer periphery 15A of the second electrode layer 15 that blocks light overlaps the first electrode layer 13 via the first oxide semiconductor layer 14, light incident from the second electrode layer 15 side. Can be detected.

  In addition, the optical sensor 1 according to Embodiment 1 of the present invention has a change in current value between the second electrode layer 15 and the third electrode layer 16, that is, the stacked second electrode layer 15 and first electrode layer 13. Light is detected by a change in current value between and. Therefore, it is possible to increase the resistance value between the second electrode layer 15 and the first electrode layer 13 by increasing the thickness of the first oxide semiconductor layer 14. Therefore, even if the resistance value between the second electrode layer 15 and the first electrode layer 13 is increased in order to reduce power consumption during use, the size of the photosensor 1 is the same as that of the second electrode layer 15. Although it increases in the direction of stacking, it does not increase in the horizontal direction of the substrate 11. Therefore, the number of photosensors that can be obtained from one wafer is increased, and the area of the photosensor 1 that occupies the circuit board to be mounted is reduced, so that the integration rate of components on the circuit board can be improved.

  In addition, the optical sensor 1 according to Embodiment 1 of the present invention reduces the carriers contained in the first oxide semiconductor layer 14 and increases the resistance value between the second electrode layer 15 and the first electrode layer 13. By doing so, the distance between the second electrode layer 15 and the first electrode layer 13 can be shortened, and the electric field between the second electrode layer 15 and the first electrode layer 13 can be strengthened. Sensitivity can be increased.

  Furthermore, the optical sensor 1 according to Embodiment 1 of the present invention has a configuration in which the first electrode layer 13, the first oxide semiconductor layer 14, and the second electrode layer 15 are stacked on the substrate 11. As in the optical sensor disclosed in FIG. 4, the current leaks to the metal film on the substrate, and the thickness of the first oxide semiconductor layer 14 can be reduced to reduce the manufacturing cost. It becomes.

(Embodiment 2)
FIG. 7 is a schematic diagram showing the configuration of the optical sensor 1 according to Embodiment 2 of the present invention. Fig.7 (a) is a top view which shows the structure of the optical sensor 1 which concerns on Embodiment 2 of this invention. FIG. 7B is a BB cross-sectional view of the optical sensor 1 shown in FIG. As shown in FIG. 7B, in the optical sensor 1 according to Embodiment 2 of the present invention, the first oxide semiconductor layer 14 is not a ZnO film containing a small amount of carriers, but a BST (a small amount of carriers). (Ba, Sr) TiO ₃ ) film. The BST film is formed on the insulating layer 12 and the first electrode layer 13 with a thickness of 400 nm by sputtering. In addition, since the BST film has a band gap of 4.3 eV, when used in the optical sensor 1, light (ultraviolet light) having a wavelength of 290 nm or less can be detected. The other configuration is the same as the configuration of the optical sensor 1 according to the first embodiment shown in FIG.

  As shown in FIG. 7A, the shape of the second electrode layer 15 is not a rectangle but a so-called comb shape. By making the shape of the second electrode layer 15 comb-shaped, the length of the outer periphery 15B of the second electrode layer 15 is longer than the length of the outer periphery 15A when the shape of the second electrode layer 15 is rectangular. become longer. As the outer periphery 15B of the second electrode layer 15 becomes longer, the portion where the outer periphery 15B of the second electrode layer 15 overlaps the first electrode layer 13 through the first oxide semiconductor layer 14 increases, and the second electrode layer 15 side As a result, the number of electron / hole pairs generated by the incident light increases, and the change in the current value between the second electrode layer 15 and the third electrode layer 16 increases, and the sensitivity of the photosensor 1 increases.

  As described above, in the optical sensor 1 according to Embodiment 2 of the present invention, the second electrode layer 15 is compared with the outer periphery 15A when the second electrode layer 15 has a rectangular shape. Since the outer periphery 15B of the electrode is long, when the light enters from the second electrode layer 15 side, the change in the current value between the second electrode layer 15 and the third electrode layer 16 increases, and the optical sensor The sensitivity of 1 becomes high.

  The shape in which the outer periphery 15B of the second electrode layer 15 is longer than the outer periphery 15A when the shape of the second electrode layer 15 is rectangular is not limited to the comb shape, but is a stripe shape, mesh A shape, a meander shape, or the like may be used. In addition, the shape of the second electrode layer 15 of the optical sensor 1 according to the second embodiment can be applied to the shape of the second electrode layer 15 according to the first embodiment.

(Embodiment 3)
FIG. 8 is a schematic diagram showing the configuration of the optical sensor 1 according to Embodiment 3 of the present invention. As shown in FIG. 8, in the optical sensor 1 according to Embodiment 3 of the present invention, the first oxide semiconductor layer 14 is not a ZnO film containing a trace amount of carriers but a Cu ₂ O film containing a trace amount of carriers. is there. The Cu ₂ O film is formed on the first electrode layer 13 with a thickness of 700 nm by sputtering. Further, since the Cu ₂ O film has a band gap of 2.0 eV, when it is used for the optical sensor 1, it can detect light having a wavelength of 620 nm or less.

Furthermore, in the optical sensor 1 according to Embodiment 3 of the present invention, the second oxide semiconductor layer 18 is laminated between the third electrode layer 16 and the first electrode layer 13. The second oxide semiconductor layer 18 is a Cu ₂ O film containing a trace amount of carriers, and is electrically connected to the first oxide semiconductor layer 14 via the first electrode layer 13. Further, in the optical sensor 1 according to Embodiment 3 of the present invention, the outer periphery 16A of the third electrode layer 16 that blocks incident light is overlapped with the first electrode layer 13 with the second oxide semiconductor layer 18 interposed therebetween. Therefore, when light is incident from the third electrode layer 16 side, electron-hole pairs are generated in the second oxide semiconductor layer 18 in the vicinity of the outer periphery 16A of the third electrode layer 16, and the third electrode layer 16 The current value between the first electrode layer 13 changes and light can be detected.

  That is, the optical sensor 1 according to Embodiment 3 of the present invention includes an optical sensor including the second electrode layer 15, the first oxide semiconductor layer 14, and the first electrode layer 13, the third electrode layer 16, The optical sensor composed of the second oxide semiconductor layer 18 and the first electrode layer 13 is connected in series. For this reason, the optical sensor 1 according to Embodiment 3 of the present invention can increase the resistance value between the second electrode layer 15 and the third electrode layer 16, thereby further reducing power consumption during use. Can do. The other configuration is the same as the configuration of the optical sensor 1 according to the first embodiment shown in FIG.

  As described above, the optical sensor 1 according to Embodiment 3 of the present invention is electrically connected to the first oxide semiconductor layer 14 via the first electrode layer 13, and is connected to the third electrode layer 16 and the first electrode. The second oxide semiconductor layer 18 stacked between the electrode layer 13 is provided, and at least a part of the outer periphery 16A of the third electrode layer 16 that blocks incident light is interposed via the second oxide semiconductor layer 18. Since it overlaps with the first electrode layer 13, the resistance value between the second electrode layer 15 and the third electrode layer 16 can be increased, so that the power consumption during use can be further suppressed.

  The material of the second oxide semiconductor layer 18 is not limited to the case where the material is the same as that of the first oxide semiconductor layer 14, and may be a material different from that of the first oxide semiconductor layer 14. The shape of the second electrode layer 15 according to the second embodiment can be applied to the shape of the second electrode layer 15 and the third electrode layer 16 according to the third embodiment.

(Embodiment 4)
FIG. 9 is a schematic diagram showing the configuration of the optical sensor 1 according to Embodiment 4 of the present invention. As shown in FIG. 9, the optical sensor 1 according to the fourth embodiment of the present invention uses a glass substrate 19 instead of a substrate 11 that is a Si substrate, and a first electrode layer 13 on the glass substrate 19. The second electrode layer 15, the second oxide semiconductor layer 18, and the third electrode layer 16 are stacked.

  Since the glass substrate 19 transmits light, the optical sensor 1 that detects light incident from the glass substrate 19 side can be realized. The first electrode layer 13 is laminated on the glass substrate 19, and is composed of two layers of a Ti film 13a and a Pt film 13b. The second electrode layer 15 is laminated in a partial region on the first electrode layer 13, and is composed of three layers of a Ti film 15a, a Ni film 15c, and an Au film 15b. The second oxide semiconductor layer 18 is a ZnO film that is stacked in a region on the first electrode layer 13 that is different from the region where the second electrode layer 15 is stacked, and contains a small amount of carriers. The third electrode layer 16 is laminated on the second oxide semiconductor layer 18, and is composed of three layers of a Ti film 16a, a Ni film 16c, and an Au film 16b. The other configuration is the same as the configuration of the optical sensor 1 according to the first embodiment shown in FIG.

  Unlike the optical sensor 1 according to the first embodiment, the optical sensor 1 according to the fourth embodiment of the present invention detects light incident from the glass substrate 19 side. Therefore, the electrode layer that blocks incident light is the first electrode layer 13 so that at least a part of the outer periphery 13A of the first electrode layer 13 overlaps the third electrode layer 16 with the second oxide semiconductor layer 18 interposed therebetween. In addition, the second electrode layer 15, the second oxide semiconductor layer 18, and the third electrode layer 16 are stacked on the glass substrate 19. Therefore, in the optical sensor 1 according to Embodiment 4 of the present invention, when light is incident from the glass substrate 19 side, electrons / holes are formed in the second oxide semiconductor layer 18 in the vicinity of the outer periphery 13A of the first electrode layer 13. A pair is generated, and the current value between the third electrode layer 16 and the first electrode layer 13 changes, so that light can be detected. Since the second electrode layer 15 is electrically connected to the first electrode layer 13, it has the same potential as the first electrode layer 13. Therefore, the current value between the second electrode layer 15 and the third electrode layer 16 can be measured by measuring the current value between the first electrode layer 13 and the third electrode layer 16.

  As described above, the optical sensor 1 according to Embodiment 4 of the present invention can detect light incident from the glass substrate 19 side by using the glass substrate 19, and can detect the second electrode layer 15 and the third electrode. The layer 16 side can be soldered directly to the circuit board. Note that, in the optical sensor 1 according to Embodiment 4 of the present invention, solder bumps may be provided on the second electrode layer 15 and the third electrode layer 16 as necessary. Unlike the optical sensor 1 according to the first embodiment, there is no need to arrange wires for extracting signals from the second electrode layer 15 and the third electrode layer 16 after mounting, and the optical sensor according to the fourth embodiment. Since 1 is solder-mounted directly on the circuit board, the manufacturing cost is reduced.

  The optical sensor 1 according to the fourth embodiment of the present invention is not limited to the configuration in which the first electrode layer 13, the second oxide semiconductor layer 18, and the third electrode layer 16 are stacked. Even in the configuration in which the first oxide semiconductor layer 14 is further laminated between the first electrode layer 13 and the second electrode layer 15, the first electrode layer 13 and the second electrode semiconductor layer 18 are not laminated. The first oxide semiconductor layer 14 may be stacked between the second electrode layer 15 and the second electrode layer 15. However, when the first oxide semiconductor layer 14 is stacked between the first electrode layer 13 and the second electrode layer 15, the electrode layer that blocks incident light is the first electrode layer 13, and the first electrode layer 13, the first electrode semiconductor layer 14, the first oxide semiconductor layer 14, and the second electrode layer 15 so that at least a part of the outer periphery 13 </ b> A overlaps the second electrode layer 15 with the first oxide semiconductor layer 14 interposed therebetween. Need to be laminated.

  Further, the shape of the second electrode layer 15 according to the second embodiment can be applied to the shape of the first electrode layer 13 according to the fourth embodiment. Furthermore, also in the optical sensor 1 according to the fourth embodiment, the material of the second oxide semiconductor layer 18 is different from the material of the first oxide semiconductor layer 14 as in the optical sensor 1 according to the second embodiment. Anyway.

DESCRIPTION OF SYMBOLS 1 Optical sensor 11 Board | substrate 12, 17 Insulating layer 13 1st electrode layer 13A Periphery 13a, 15a of the 1st electrode layer, 16a Ti film 13b Pt film 15b, 16b Au film 14 1st oxide semiconductor layer 14A 1st oxide semiconductor Layer outer periphery 15 second electrode layer 15A, 15B second electrode layer outer periphery 15c, 16c Ni film 16 third electrode layer 16A third electrode layer outer periphery 18 second oxide semiconductor layer 19 glass substrate 41 light shielding film

Claims (13)

A substrate,
A first electrode layer laminated on the substrate;
A first oxide semiconductor layer stacked in a partial region on the first electrode layer;
A second electrode layer laminated on the first oxide semiconductor layer,
At least a part of the outer periphery of the first electrode layer or the second electrode layer that blocks incident light is overlapped with the second electrode layer or the first electrode layer with the first oxide semiconductor layer interposed therebetween. An optical sensor characterized by being.   The optical sensor according to claim 1, further comprising a third electrode layer stacked in a region on the first electrode layer different from a region in which the first oxide semiconductor layer is stacked. A second oxide semiconductor layer electrically connected to the first oxide semiconductor layer via the first electrode layer, the second oxide semiconductor layer being stacked between the third electrode layer and the first electrode layer;
At least a part of the outer periphery of the first electrode layer or the third electrode layer that blocks incident light is overlapped with the third electrode layer or the first electrode layer with the second oxide semiconductor layer interposed therebetween. The optical sensor according to claim 1, wherein the optical sensor is provided.   The optical sensor according to claim 3, wherein the second oxide semiconductor layer is a ZnO film. The optical sensor according to claim 3, wherein the second oxide semiconductor layer is a (Ba, Sr) TiO ₃ film. The optical sensor according to claim 3, wherein the second oxide semiconductor layer is a Cu ₂ O film.   The optical sensor according to claim 1, wherein the first oxide semiconductor layer is a ZnO film. The optical sensor according to claim 1, wherein the first oxide semiconductor layer is a (Ba, Sr) TiO ₃ film. The optical sensor according to claim 1, wherein the first oxide semiconductor layer is a Cu ₂ O film.   The optical sensor according to claim 3, wherein a material of the second oxide semiconductor layer is different from a material of the first oxide semiconductor layer.   The first electrode layer or the second electrode layer that blocks incident light is different from the first electrode layer or the second electrode compared to the case where the shape of the first electrode layer or the second electrode layer is rectangular. The optical sensor according to claim 1, wherein the outer periphery of the layer has a long shape.   The first electrode layer or the third electrode layer that blocks incident light is different from the first electrode layer or the third electrode layer as compared with the case where the shape of the first electrode layer or the third electrode layer is rectangular. The optical sensor according to claim 1, wherein the outer periphery of the layer has a long shape.   The optical sensor according to claim 1, wherein the substrate is made of a material that transmits light.

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