JP5214329B2 - UV sensor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a UV sensor using an SOI substrate and a manufacturing method thereof.

  In an SOI (Silicon On Insulator) device, a first semiconductor layer (hereinafter referred to as a semiconductor substrate layer) and a second semiconductor layer (hereinafter referred to as an SOI layer) formed thereon are insulated and separated by a buried oxide film. Has a structure. As a result, the isolation between adjacent elements can be easily performed, and a parasitic thyristor is not formed through the semiconductor substrate layer, so that a latch-up phenomenon can be prevented. In addition, forming a transistor in an SOI layer over an insulating film is effective in suppressing a so-called short channel effect in which power consumption increases with miniaturization of the transistor. Furthermore, since the junction capacitance of a transistor formed with an SOI structure is smaller than that of a transistor with a bulk structure, high-speed operation is possible. As described above, a transistor having an SOI structure has excellent characteristics and is expected as a device capable of achieving higher speed and lower power consumption than a semiconductor element formed on a conventional bulk substrate.

  Attempts have been made to adapt a wafer having this SOI structure (hereinafter referred to as an SOI substrate) to a UV sensor. Since the conventional UV sensor uses a compound semiconductor such as gallium nitride, it is difficult to mount a peripheral circuit on the same chip. In addition, in the case of a UV sensor using a silicon substrate, since it has sensitivity to light in a wide wavelength range, an optical filter for blocking visible light is required, resulting in high manufacturing cost and low sensitivity. . Since the influence of noise through the substrate is reduced, the UV sensor using the SOI substrate can adopt a high-density layout in which peripheral circuits such as an operational amplifier are built in the same chip. In addition, a UV sensor using an SOI substrate can form a photodiode having sensitivity only to UV light by thinning the SOI layer, and can obtain good spectral sensitivity characteristics without using an optical filter. Therefore, there is a merit that it is possible to achieve downsizing with high portability at low cost.

Patent Documents 1 and 2 disclose a UV sensor having sensitivity only to UV light without using a transmission filter by using an SOI substrate.
JP-A-7-162024 JP-A-7-162025

  In a conventionally known UV sensor, in order to detect only ultraviolet rays in a predetermined wavelength region, the thickness of the SOI layer is designed to be thin or the thickness of the SOI layer serving as the light receiving region of the UV sensor is set to other portions. There was a known way to make it thinner.

  However, if ions are implanted at a high dose into a thin SOI layer, the entire SOI layer becomes amorphous in the SOI layer with a certain thickness or less, and recrystallization occurs randomly in the subsequent heating process. There is a problem. In particular, crystal defects frequently occur in a light-receiving region with a small thickness, and there has been a problem that fatal characteristics are deteriorated, such as a decrease in light-receiving sensitivity of the UV sensor.

  Further, when a predetermined voltage is applied to the UV sensor, the depletion layer formed by the PN junction formed in the light receiving region may extend to other than the light receiving region, and when the depletion layer extends to other than the light receiving region, the UV sensor. There is also a problem that fatal characteristic deterioration such as a decrease in light receiving sensitivity occurs.

  The present invention has been made in view of the circumstances as described above, and provides a UV sensor capable of preventing a decrease in light receiving sensitivity and a method for manufacturing the same.

In order to solve the above-described problems, a UV sensor according to the present invention is a UV sensor formed on an SOI substrate in which a semiconductor layer is stacked on a buried oxide film, and is juxtaposed along the buried oxide film. A light-receiving region including a low-concentration N-type region and a low-concentration P-type region that are PN-junctioned, a high-concentration N-type region in contact with a portion of the low-concentration N-type region excluding a bonding surface that forms the PN junction, A high-concentration P region in contact with a portion of the low-concentration P-type region excluding the junction surface forming the PN junction, and at least one of the low-concentration N-type region and the low-concentration P-type region. parts that further having a least permeability transparent protective film allowed to transmit UV light to cover the.

  The thicknesses of the low-concentration N-type region and the low-concentration P-type region may be thinner than at least a part of the thickness of the high-concentration N-type region and the high-concentration P-type region.

  In order to solve the above-described problems, a preparation step of preparing an SOI substrate, a groove portion forming step of forming a groove portion by etching a semiconductor layer of the SOI substrate, and a low concentration N in a part of the groove portion A low concentration N type region forming step for forming a mold region by ion implantation, and a low concentration P type region forming step for forming a low concentration P type region in contact with the concentration N type region and forming a PN junction therewith by ion implantation A high-concentration N-type region forming step of ion-implanting a high-concentration N-type region in contact with a portion of the low-concentration N-type region excluding the bonding surface forming the PN junction, and the low-concentration P-type region A high-concentration P-type region forming step of forming a high-concentration P-type region in contact with a portion excluding the bonding surface forming the PN junction by ion implantation, and in the low-concentration N-type region forming step, Wherein the position-depletion by the PN junction which is calculated not to reach the other than the groove by setting value method for producing a UV sensor, which comprises forming a lightly doped N-type region is provided.

  The predetermined set value may be a layer thickness of the groove, a dose of ion implantation for forming the low concentration N-type region, and an applied voltage applied to the semiconductor layer. Furthermore, the applied voltage may be a maximum applied voltage when the UV sensor manufactured by the manufacturing method is used.

  In order to solve the above-described problems, a preparation step of preparing an SOI substrate, a groove portion forming step of forming a groove portion by etching a semiconductor layer of the SOI substrate, and a low concentration N in a part of the groove portion A low concentration N type region forming step for forming a mold region by ion implantation, and a low concentration P type region forming step for forming a low concentration P type region in contact with the concentration N type region and forming a PN junction therewith by ion implantation A high-concentration N-type region forming step of ion-implanting a high-concentration N-type region in contact with a portion of the low-concentration N-type region excluding the bonding surface forming the PN junction, and the low-concentration P-type region A high-concentration P-type region forming step of forming a high-concentration P-type region in contact with a portion excluding the bonding surface for forming a PN junction by ion implantation. In the low-concentration N-type region forming step, Method for producing a UV sensor, which comprises forming the low-concentration N-type region by ion dose implantation amorphization does not occur in the low-concentration N-type region which is calculated by the layer thickness of the groove.

  In the low-concentration N-type region forming step, a depletion layer due to the PN junction calculated by a dose amount of ion implantation that does not cause amorphization, a layer thickness of the groove, and a voltage applied to the semiconductor layer The low-concentration N-type region may be formed at a position that does not reach other than the groove.

  Further, the applied voltage may be a maximum applied voltage when the UV sensor manufactured by the manufacturing method is used.

  A low-concentration N-type region formed in a semiconductor layer of an SOI substrate, and a low-concentration P-type region that is in contact with the low-concentration N-type region and forms a PN junction with the low-concentration N-type region and the low-concentration region Since it is sandwiched between the high-concentration N-type region and the high-concentration P-type region having a higher concentration than each of the concentration P-type regions, crystal defects due to amorphization of the portion that receives UV light are prevented, and the light receiving sensitivity of the UV sensor is reduced. Can be prevented.

  Also, a preparatory step for preparing an SOI substrate, a groove forming step for forming a groove by etching the semiconductor layer of the SOI substrate, and a low concentration N-type region formed by ion implantation in a part of the groove. A concentration N-type region forming step, a low-concentration P-type region forming step of forming a low-concentration P-type region in contact with the concentration N-type region to form a PN junction by ion implantation, and the low-concentration N-type region A high-concentration N-type region forming step for forming a high-concentration N-type region in contact with a portion excluding the joint surface for forming the PN junction by ion implantation, and a joint surface for forming the PN junction in the low-concentration P-type region are excluded. A high-concentration P-type region forming step of forming a high-concentration P-region region in contact with the portion by ion implantation, and in the low-concentration N-type region forming step, before calculation with a predetermined set value Because the depletion layer due to a PN junction to form the low concentration N-type region at the position does not reach the other than the groove, it is possible to prevent a reduction in light-receiving sensitivity of the UV sensor.

  Also, a preparatory step for preparing an SOI substrate, a groove forming step for forming a groove by etching the semiconductor layer of the SOI substrate, and a low concentration N-type region formed by ion implantation in a part of the groove. A concentration N-type region forming step, a low-concentration P-type region forming step of forming a low-concentration P-type region in contact with the concentration N-type region to form a PN junction by ion implantation, and the low-concentration N-type region A high-concentration N-type region forming step for forming a high-concentration N-type region in contact with a portion excluding the joint surface for forming the PN junction by ion implantation, and a joint surface for forming the PN junction in the low-concentration P-type region are excluded. A high-concentration P-type region forming step of forming a high-concentration P-region region in contact with the portion by ion implantation, and in the low-concentration N-type region forming step, the thickness is calculated by the layer thickness of the groove Serial Because of forming the lightly doped N-type region by ion dose implantation amorphization in the low concentration N-type region does not occur, it is possible to prevent a reduction in light-receiving sensitivity of the UV sensor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, the structure of a UV sensor 10 as an embodiment of the present invention will be described in detail with reference to FIG.

  As shown in FIG. 1, the structure of the UV sensor 10 includes a semiconductor substrate layer 11 that is a first semiconductor layer, a buried oxide film 12 formed on the semiconductor substrate layer 11, and a stack on the buried oxide film 12. The second semiconductor layer is an SOI layer 13 and a transparent protective film 14 covering the SOI layer 13. An SOI substrate 15 is formed from the semiconductor substrate layer 11, the buried oxide film 12, and the SOI layer 13.

The SOI layer 13 has a central portion whose thickness is thinner than the surroundings, and a groove 13 a is formed on the surface of the SOI layer 13. A low concentration N-type region 16 (hereinafter referred to as N ⁻ region 16) and a low concentration P type region 17 (hereinafter referred to as P ⁻ region 17) are formed in the groove 13a. Further, since the N ⁻ region 16 and the P ⁻ region 17 are in contact with each other, a PN junction is formed, and a photodiode is formed by the PN junction N ⁻ region 16 and the P ⁻ region 17. A region where the N ⁻ region 16 and the P ⁻ region 17 are formed becomes a light receiving region 18. Since the thickness of the SOI layer 13 in the groove 13a is a predetermined thickness that generates sensitivity only in the wavelength in the UV region, the UV sensor 10 can have sensitivity only in the wavelength in the UV region of the irradiated light. It becomes. For example, the thickness of the SOI layer 13 in the groove 13a is desirably 30 nm.

Around the light receiving region 18, a high concentration N-type region 19 (hereinafter referred to as an N ⁺ region 19) and a high concentration P type region 20 (hereinafter referred to as a P ⁺ region 20) are formed. Specifically, the N ⁺ region 19 is formed in contact with the portion of the N ⁻ region 16 except for the PN junction surface, and the P ⁺ region 20 is formed in contact with the portion of the P ⁻ region 17 except for the PN junction surface. . That is, the N ⁻ region 16 and the low concentration P-type region 17 forming the PN junction are sandwiched between the N ⁺ region 19 and the P ⁺ region 20. A contact (not shown) such as an aluminum electrode is formed in the N ⁺ region 19 and the P ⁺ region 20, and a desired negative voltage is applied to the SOI layer 13 through the contact. For such voltage application, an N ⁺ region 19 and a P ⁺ region 20 having an impurity concentration higher than that of the light receiving region 18 are formed across the light receiving region 18. Even when high concentration impurities are ion-implanted, the N ⁺ region 19 and the P ⁺ region 20 are thicker than the light receiving region 18 from the viewpoint of preventing the entire region from becoming amorphous. For example, the layer thickness of the N ⁺ region 19 and the P ⁺ region 20 is desirably 50 nm.

The P ⁺ region 20 may be partially formed in the light receiving region 18 (that is, the groove 13a), but the N ⁺ region 19 is not formed in the light receiving region 18. This is because if the N ⁺ region 19 is formed in a portion having a thin layer thickness, the portion becomes completely amorphous in the thickness direction of the layer, and crystal defects are generated by the subsequent heat treatment.

The transparent protective film 14 is a transparent transparent protective film that transmits at least UV light. The transparent protective film 14 may partially cover the N ⁻ region 16 and the P ⁻ region 17 without covering the entire SOI layer 13. In such a case, the portion covered with the transparent protective film 14 becomes the light receiving region.

From the above-described configuration, the SOI layer 13 is formed with a lateral diode including the N ⁺ region 19, the N ⁻ region 16, the P ⁻ region 17, and the N ⁺ region 20.

Next, a specific amount of the dose of the N ⁻ region 16 will be described with reference to FIG.

FIG. 2A is a graph showing the relationship between the dose in the N ⁻ region 16 and the total depletion layer generated by the PN junction. The layer thickness of the light receiving region 18 is 30 nm. The horizontal axis of the graph is the dose amount in the N ⁻ region 16 and the vertical axis is the width of the depletion layer. In the graph, the results are shown in which the voltages applied to the contacts formed in the N ⁺ region 19 and the N ⁺ region 20 are 0V and −3.6V.

As shown in the graph, it can be seen that the fluctuation of the depletion layer width increases when the dose amount is small. Since the light reception sensitivity of the UV sensor 10 is determined by the volume of the depletion layer, the light reception sensitivity of the UV sensor 10 varies when the width of the depletion layer varies. Therefore, in order to reduce the change in the depletion layer width (for example, the change rate is within 1%), when the layer thickness of the light receiving region 18 is 30 nm, the dose amount is 2.5 × 10 ¹³ (cm ^−2). It is desirable to perform ion implantation as described above. In order to prevent the entire N ⁻ region 16 from becoming amorphous, it is desirable to perform ion implantation with a dose amount of 1.0 × 10 ¹⁴ (cm ⁻² ) or less.

  Next, the position of the PN junction surface in the groove 13a will be described with reference to FIG.

2 (b) is, N ^- caused by a dose of the PN junction in the area 16 N ^- is a graph showing the relationship between the depletion layer generated in the region 16. The layer thickness of the light receiving region 18 is 30 nm. The horizontal axis of the graph represents the dose amount in the N ⁻ region 16, and the vertical axis represents the width of the depletion layer generated in the N ⁻ region 16. In the graph, the results are shown in which the voltages applied to the contacts formed in the N ⁺ region 19 and the N ⁺ region 20 are 0V and −3.6V.

From the result shown in FIG. 2A, the dose amount in the N ⁻ region 16 is desirably 2.5 × 10 ¹³ (cm ⁻² ) or more and 1.0 × 10 ¹⁴ (cm ⁻² ) or less. When ion implantation is performed with such a dose, the maximum depletion layer in the N ⁻ region 16 is about 9.0 nm from the result of FIG. That is, when the PN coupling surface is 9.0 nm or less from the N ⁺ region 19, the depletion layer reaches the N ⁺ region 19 other than the light receiving region 18. When the depletion layer extends to the SOI layer 13 other than the light receiving region 18, only UV light is generated due to reflection components at the boundary between the semiconductor substrate layer 11 and the buried oxide film 12 and at the boundary between the buried oxide film 12 and the SOI layer 13. In addition, the sensitivity is generated even in visible light (wavelength of 400 nm or more), and the characteristics of the UV sensor 10 may be lost. Accordingly, in the above-described case, it is desirable to provide the PN junction surface at a position spaced 9 nm or more from the N ⁺ region 19 so that the depletion layer is generated only in the light receiving region 18.

The doses of the other SOI layers 13 in the specific examples described above are 5.0 × 10 ¹⁵ (cm ⁻² ) for the N ⁺ region 19 and the P ⁺ region 20 and 2.2 × 10 ^{12 for the} P ⁻ region 17. (Cm ⁻² ) is desirable.

  Next, a method for manufacturing the UV sensor 10 as an embodiment of the present invention will be described in detail with reference to FIG.

First, an SOI substrate 15 including a semiconductor substrate layer 11, a buried oxide film 12, and an SOI layer 13 is prepared (FIG. 3A). The SOI substrate 15 may be formed by a method such as a bonding method or a SIMOX (Silicon Implanted Oxide) method. Incidentally, high energy and high concentration oxygen ions are implanted from the prime wafer surface by the SIMOX method, and then the implanted oxygen and silicon are reacted by heat treatment to form an insulating layer made of SiO _{2 in the} vicinity of the wafer surface. On the other hand, in the bonding method, an SOI substrate is formed by bonding a wafer having a SiO ₂ film on the surface and a wafer different from the wafer by heat and pressure, and grinding and removing one wafer halfway. The SOI layer 13 may be a P-type or N-type semiconductor substrate.

  Next, a part of the SOI layer 13 is etched away to form a groove 13a that becomes the light receiving region 18 after ion implantation for receiving UV light (FIG. 3B). Here, the layer thickness of the groove 13a needs to be etched to a thickness that generates sensitivity only to the wavelength of the received UV light. For example, the layer thickness after etching is desirably 30 nm.

Next, after forming a photomask having an opening with a predetermined width on the SOI substrate 15 from the end of the groove 13a, phosphorus ions are implanted through the opening to form the N ⁻ region 16 in the SOI layer 13. (FIG. 3C). The formation position and the width of the N ⁻ region 16 are previously applied to the layer thickness of the SOI layer 13 in the light receiving region 18 (that is, the groove 13 a) of the UV sensor 10, the dose of ion implantation in the N ⁻ region 16, and the SOI layer 13. From the relationship of applied voltage (for example, the maximum applied voltage when the UV sensor 10 is used), a simulation is performed on the growth of the depletion layer in the N ⁻ region 16, and from the simulation result, the depletion layer becomes the groove 13 a of the SOI layer 13. It is determined within the range not reaching. For example, when the ion implantation dose is 2.5 × 10 ¹³ (cm ⁻² ) or more and 1.0 × 10 ¹⁴ (cm ⁻² ) or less, the implantation width of phosphorus (that is, the opening width of the photomask). ) Is set to 9 nm or more from the end of the groove 13a formed in the SOI layer 13. By such a method for determining the formation position of the N ⁻ region 16 and its width, the depletion layer does not extend beyond the trench 13 a of the SOI layer 13, and it is possible to prevent a decrease in light receiving sensitivity.

Next, after removing the photomask to form the N ⁻ region 16, a photomask having an opening is formed in the groove 13 a of the SOI layer 13 where phosphorus is not implanted in the above-described step. Then, boron is ion-implanted to form a P ⁻ region 17 (FIG. 3D). That is, the N ⁻ region 16 and the P ⁻ region 17 are formed so as to be juxtaposed along the surface of the SOI layer 13, thereby forming a PN junction. For example, the dose amount of ion implantation in this step may be about 2.2 × 10 ¹² (cm ⁻² ).

Next, after removing the photomask to form the P ⁻ region 17, a photomask having an opening in a portion where the layer thickness is 30 nm or more is in contact with the portion except the PN junction surface of the N ⁻ region 16. Then, phosphorus is ion-implanted through the opening to form an N ⁺ region 19 in the SOI layer 13. Further, after removing the photomask to form the N ⁺ region 19, a photomask having an opening at a portion having a layer thickness of 30 nm or more is formed at a position in contact with the portion except the PN junction surface of the P ⁻ region 17. Then, boron is ion-implanted through the opening to form the P ⁺ region 20 in the SOI layer 13. (FIG. 3 (e)).

After the lateral diode composed of the N ⁺ region 19, the N ⁻ region 16, the P ⁻ region 17 and the P ⁺ region 20 is formed on the SOI layer 13, a transparent protective film 14 is formed so as to cover the SOI layer 13 (FIG. 3). (F)). The transparent protective film 14 may be formed only on a part of the groove 13 a of the SOI layer 13.

Further, a contact such as an aluminum electrode electrically connected to the N ⁺ region 19 and the P ⁺ region 20 is formed by sputtering or the like. The UV sensor 10 is completed through the above steps.

As described above, according to the UV sensor of the present embodiment, the N ⁻ region 16 formed in the SOI layer 13 of the SOI substrate 15 and the P ⁻ region 17 in contact with the N ⁻ region 16 and forming a PN junction therewith. Are sandwiched between the N ⁺ region 19 and the P ⁺ region 20 having a higher concentration than the N ⁻ region 16 and the P ⁻ region 17, respectively, so that crystal defects due to amorphization of the portion that receives UV light can be prevented and the UV sensor Decrease in light receiving sensitivity can be prevented.

Also, N ^- in the step of forming the region 16, the layer thickness of the SOI layer 13 of the light-receiving region 18 of the UV sensor 10 is a predetermined set value, N ^- is applied to the dose and the SOI layer 13 of the ion implantation in the region 16 Since the N ⁻ region 16 is formed at a position where the depletion layer due to the PN junction does not reach other than the groove 13a, which is calculated from the relationship of the applied voltage, it is possible to prevent the light receiving sensitivity of the UV sensor 10 from being lowered. .

In the embodiment described above, the display density of the P ⁺ region, P ⁻ region, N ⁺ region, and N ⁻ region means that P ⁺ > P ⁻ and N ⁺ > N ⁻ , and the absolute value of the concentration is Not a standard.

  In the first embodiment, the depletion layer due to the PN junction is set so as not to extend beyond the groove 13 a of the SOI layer 13, thereby preventing the light receiving sensitivity from being lowered and preventing the deterioration of the characteristics of the UV sensor 10. A manufacturing method is described. As a different method for preventing the light receiving sensitivity from decreasing, a manufacturing method for preventing the light receiving sensitivity from decreasing from the viewpoint of preventing the light receiving region 18 from becoming amorphous will be described. Since the structure of the UV sensor 10 is the same as that of the first embodiment, the description thereof is omitted.

  First, since the manufacturing method from FIG. 3A to FIG. 3B is the same as that of the first embodiment, the description thereof is omitted.

Next, after forming the groove 13a to be the light receiving region 18, a photomask having an opening with a predetermined width is formed on the SOI substrate 15 from the end of the groove 13a, and then phosphorus is ion-implanted through the opening. An N ⁻ region 16 is formed in the SOI layer 13 (FIG. 3C). Here, since the thickness of the SOI layer 13 of the groove 13a to be the light receiving region 18 is determined depending on which wavelength of the UV light has sensitivity, the thickness is determined in advance. . For example, the thickness of the SOI layer 13 in the groove 13a is 30 nm. Therefore, the dose amount of ion implantation that does not cause amorphization in the layer thickness of the SOI layer 13 in the groove 13a is calculated in advance, and the N ⁻ region 16 is formed with the dose amount of ion implantation corresponding to the calculation result. And By determining the dose amount of the ion implantation in the N ⁻ region 16 as described above, it is possible to prevent occurrence of amorphization in the light receiving region 18 and to prevent a decrease in light receiving sensitivity.

  The subsequent manufacturing method up to the completion of the UV sensor 10 is the same as that in the first embodiment, and the description thereof will be omitted.

As described above, according to the manufacturing method of the UV sensor according to the present embodiment, the N ⁻ region 16 is formed by the dose amount of ion implantation that does not cause amorphization in the N ⁻ region 16 calculated by the layer thickness of the groove 13a. Therefore, a decrease in the light receiving sensitivity of the UV sensor 10 can be prevented.

In the second embodiment, the N ⁻ region 16 is formed with the dose of ion inflow that does not cause amorphization when the N ⁻ region 16 is formed, thereby preventing the light receiving sensitivity from decreasing and the UV sensor 10. The manufacturing method which prevents the characteristic deterioration of is described. However, the dose of ion implantation at which amorphization does not occur is smaller than that of conventional ion implantation, and the width of the depletion layer due to the PN junction is reduced as shown in FIGS. It turns out to be long. Therefore, if the N ⁻ region 16 is formed with a dose amount of ion implantation for preventing amorphization, there is a high possibility that a depletion layer due to the PN junction extends beyond the groove 13 a of the SOI layer 13.

As a method for solving such a problem, after determining the dose amount of ion implantation for preventing amorphization, N is determined from the relationship between the dose amount, the thickness of the SOI layer 13 in the light receiving region 18 and the applied voltage of the UV sensor 10. ^- determining the formation position and the width of the region 16 ^- a simulation of the extension of the depletion layer in the region 16, N within the range of the depletion layer from the result of the simulation does not reach the non-groove portion 13a of the SOI layer 13. That is, after determining the dose amount of ion implantation for preventing amorphization, which is a feature of the second embodiment, the elongation of the depletion layer, which is a feature of the first embodiment, is simulated using the dose amount. The formation position and the width of the optimum N ⁻ region 16 are determined.

As described above, the method of manufacturing the UV sensor according to the present embodiment determines the elongation of the depletion layer due to the PN junction within a range that does not reach other than the groove 13 a of the SOI layer 13 while preventing the N ⁻ region 16 from becoming amorphous. Therefore, it is possible to prevent a decrease in the light receiving sensitivity of the UV sensor 10.

It is sectional drawing of the UV sensor as an Example of this invention. (A) is N ^- a graph showing the relationship between the total depletion layer caused by a dose of the PN junction in the region, (b) is N ^- caused by a dose of the PN junction in the region N ^- depletion layer generated in the region It is the graph which showed the relationship. It is sectional drawing in each manufacturing process in the manufacturing process of UV sensor as an Example of this invention.

Explanation of symbols

10 UV sensor 11 Semiconductor substrate layer (first semiconductor layer)
12 buried oxide film 13 SOI layer (second semiconductor layer)
14 Transparent protective film 15 SOI substrate 16 Low concentration N type region (N ⁻ region)
17 Low-concentration P-type region (P ^- region)
18 Light-receiving area 19 High-concentration N-type area (N ⁺ area)
20 High-concentration P-type region (P ⁺ region)

Claims (8)

A UV sensor formed on an SOI substrate in which a semiconductor layer is stacked on a buried oxide film,
A light-receiving region including a low-concentration N-type region and a low-concentration P-type region juxtaposed to each other along the buried oxide film, and a PN junction;
A high-concentration N-type region that is in contact with a portion of the low-concentration N-type region excluding a bonding surface that forms the PN junction;
A high-concentration P region in contact with a portion of the low-concentration P-type region excluding a bonding surface that forms the PN junction;
The UV sensor further comprising a transparent transparent protective film that transmits at least UV light that covers at least a part of the low-concentration N-type region and the low-concentration P-type region.   2. The UV according to claim 1, wherein thicknesses of the low-concentration N-type region and the low-concentration P-type region are thinner than at least a part of the high-concentration N-type region and the high-concentration P-type region. Sensor. A preparation step of preparing an SOI substrate;
A groove forming step of forming a groove by etching the semiconductor layer of the SOI substrate;
A low-concentration N-type region forming step of forming a low-concentration N-type region in a part of the groove by ion implantation;
A low-concentration P-type region forming step of forming a low-concentration P-type region in contact with the concentration N-type region and forming a PN junction therewith by ion implantation;
A high-concentration N-type region forming step of forming a high-concentration N-type region in contact with a portion of the low-concentration N-type region excluding the bonding surface forming the PN junction by ion implantation;
A high-concentration P-type region forming step of forming, by ion implantation, a high-concentration P-region region that is in contact with a portion of the low-concentration P-type region excluding the bonding surface that forms the PN junction,
In the low-concentration N-type region forming step, the low-concentration N-type region is formed at a position where a depletion layer due to the PN junction calculated based on a predetermined set value does not reach other than the trench. Manufacturing method of UV sensor. Wherein the predetermined set value, the layer thickness of the groove, the claim 3, characterized in that the voltage applied to the dose and the semiconductor layer of the ion implantation for forming the low-concentration N-type region Manufacturing method of UV sensor.   5. The method of manufacturing a UV sensor according to claim 4, wherein the applied voltage is a maximum applied voltage when the UV sensor manufactured by the manufacturing method is used. A preparation step of preparing an SOI substrate;
A groove forming step of forming a groove by etching the semiconductor layer of the SOI substrate;
A low-concentration N-type region forming step of forming a low-concentration N-type region in a part of the groove by ion implantation;
A low-concentration P-type region forming step of forming a low-concentration P-type region in contact with the concentration N-type region and forming a PN junction therewith by ion implantation;
A high-concentration N-type region forming step of forming a high-concentration N-type region in contact with a portion of the low-concentration N-type region excluding the bonding surface forming the PN junction by ion implantation;
A high-concentration P-type region forming step of forming, by ion implantation, a high-concentration P-region region that is in contact with a portion of the low-concentration P-type region excluding the bonding surface that forms the PN junction,
In the low-concentration N-type region forming step, the low-concentration N-type region is formed by a dose amount of ion implantation that does not cause amorphization in the low-concentration N-type region calculated by a layer thickness of the groove. A method for manufacturing a UV sensor. In the low-concentration N-type region forming step, a depletion layer due to the PN junction calculated by a dose amount of ion implantation that does not cause amorphization, a layer thickness of the groove, and a voltage applied to the semiconductor layer is other than the groove The UV sensor manufacturing method according to claim 6, wherein the low-concentration N-type region is formed at a position that does not reach the position.   8. The method of manufacturing a UV sensor according to claim 7, wherein the applied voltage is a maximum applied voltage when the UV sensor manufactured by the manufacturing method is used.

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