KR20160053548A - Method for silicon photomultiplier using diffusion barrier and apparatus - Google Patents

Abstract

The present invention relates to a method for manufacturing a silicon photomultiplier using a diffusion prevention layer, comprising the steps of: forming a trench for dividing unit micro pixels on the middle layer; forming a PN-junction layer in a unit micro pixel region; forming a diffusion prevention layer between the PN-junction layer and a side wall of the trench; forming an insulation layer on an upper surface of a silicon photomultiplier; forming a polysilicon resistance layer on an upper surface of the insulation layer; and forming a metal electrode for connecting the polysilicon resistance layer and the PN-junction layer. The method for manufacturing a silicon photomultiplier using a diffusion prevention layer according to the present invention can prevent PN breakdown voltage from decreasing, thereby enhancing its performance.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a silicon diffraction element using a diffusion prevention layer,

The present invention relates to a Silicon PhotoMultiplier device (SiPM) using a diffusion barrier layer and a method of manufacturing the same.

Silicon Photomultiplier (SiPM) is capable of amplifying signals by a factor of one million, enabling single photon measurement, miniaturization, low operating voltage (typically 25-100V), magnetic field It has features that are not affected.

FIG. 1 is a view showing a general silicon light-diffusing element and any one of the micro-pixels included therein, and FIG. 2 is a graph showing the relationship between the doping concentration of each of the first and second bonding layers and the epitaxial layer And the electric field distribution of the active region corresponding to the application of the operating voltage.

The silicon photoemission element comprises a plurality of micro-pixels. The size of each micropixel is 25 to 100 μm, and 100 to 1000 micro pixels per 1 mm 2 area are integrated. Each micro-pixel includes a p-conductive type epitaxial layer formed on a p + conductive type substrate to a thickness of 5 탆 or less, and a pn junction formed by implanting p and n + ions in the epitaxial layer sequentially Layer (PN-junction layer).

The simple operation principle of the micro-pixel is as follows. In the PN junction layer, a very depletion region is formed as a very strong electric field is formed from the n type to the p type direction. At this time, the electrons are accelerated by an electric field in which an electron-hole pair generated by the light (photon) incident on the micro-pixel is formed. This accelerated electron-hole pair causes an Avalanche Breakdown, and the signal is amplified by the electric field discharge. Each micro-pixel operates in the Geiger region shown in Fig. 2, and the signals of all the micro-pixels in the sensor are combined into one output. 2 is a diagram showing the distribution of the electric field in the epitaxial layer in a general silicon light diffusing device.

Such a conventional silicon photoemission element includes a trench structure or a guard ring disposed between the micro-pixels to optically separate each micro-pixel from one another. That is, the trench structure or the guard ring is a structure for reducing mutual influence among the micro pixels.

Korean Patent No. 10-1113364 (entitled "Silicon Photomultiplier Tubes and Cells for the Silicon Photomultiplier Tubes") discloses a structure of a conventional silicon photodiode element and is formed between micro pixels by anisotropic etching Describes a technique for a recessed separating element.

On the other hand, in order to improve the degree of integration of micro-pixels in manufacturing a silicon photo-resist device, the line width of the pattern has been reduced. As the line width decreases, the impurity of the PN junction layer diffuses into the trench in the subsequent annealing process, so that an electric field (electric field) larger than the planar region of the PN junction is formed at the top and corner portions of the trench, .

Some embodiments of the present invention aim to propose a fabrication method that prevents the PN breakdown voltage from being reduced due to the diffusion of impurities in the PN junction layer that may occur in the fabrication of a silicon photodiode device.

According to a first aspect of the present invention, there is provided a method of manufacturing a silicon photoexposure device using a diffusion barrier layer, the method comprising: forming a trench for separating unit micro-pixels from an intermediate layer; Forming a PN junction layer between the PN junction layer and the sidewalls of the trench, forming a diffusion barrier layer between the PN junction layer and the sidewalls of the trench, forming an insulating layer on the upper surface of the silicon photoresist, And forming a metal electrode connecting the polysilicon resistive layer and the PN junction layer.

In addition, the silicon photoimageable device using the diffusion barrier layer according to the second aspect of the present invention includes a substrate, an intermediate layer on the substrate, a trench for defining a unit micro-pixel region, a PN junction layer formed on the intermediate layer, A diffusion preventing layer formed between the sidewalls of the trench, an insulating layer formed on the upper surface of the silicon light diffusing element, a polysilicon resistance layer formed on the upper surface of the insulating layer, and a metal electrode connecting the polysilicon resistance layer and the PN junction layer.

A method of manufacturing a silicon photoexposure device using a diffusion barrier layer according to a third aspect of the present invention includes the steps of forming a PN junction layer in an intermediate layer, forming a trench for separating an intermediate layer formed with a PN junction layer into unit micro- Forming a diffusion barrier layer between the PN junction layer and the sidewalls of the trench, forming an insulating layer on the top surface of the silicon photoresist, forming a polysilicon resistive layer on the top surface of the insulating layer, And forming a metal electrode connecting the resistance layer and the PN junction layer.

According to the above-mentioned object of the present invention, a diffusion preventing layer is formed between the PN junction layer and the sidewall of the trench to prevent the impurity of the PN junction layer from diffusing to the trench, thereby causing a PN breakdown voltage the breakdown voltage is prevented from being reduced, thereby improving the performance of the device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a general silicon light-diffusing element and any one of the micro-pixels included therein. FIG.
FIG. 2 is a diagram showing the electric field distribution of the active region according to application of the operating voltage, corresponding to the doping concentration of each of the first and second junction layers and epitaxial layers in the micro-pixel of FIG. 1;
FIG. 3A is a plan view of a silicon laser diffraction element using a diffusion prevention layer according to an embodiment of the present invention. FIG.
FIG. 3B is a cross-sectional view illustrating a silicon light diffusing device using a diffusion preventing layer according to an embodiment of the present invention.
4 is a flowchart illustrating a fabrication process of a silicon light diffusing device using a diffusion preventing layer according to an embodiment of the present invention.
5 is a view illustrating a manufacturing process of a silicon light diffusing device using a diffusion preventing layer according to an embodiment of the present invention.
6 is a flowchart illustrating a fabrication process of a silicon light diffusing device according to another embodiment of the present invention.
7 is a view for explaining a process of a diffusion preventing layer according to an embodiment of the present invention.
FIG. 8 is a flowchart illustrating a fabrication process of a silicon light diffusing device using a diffusion preventing layer according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

Hereinafter, a silicon photodissociation device using a diffusion prevention layer according to an embodiment of the present invention and a manufacturing method thereof will be described in detail with reference to the drawings.

FIG. 3A is a plan view of a silicon laser diffraction element using a diffusion prevention layer according to an embodiment of the present invention. FIG.

First, as shown in FIG. 3A, the substrate of the silicon light diffusing device 10 using the diffusion preventing layer according to an embodiment of the present invention is doped with a p-conductivity type or n-conductivity type, and may be a silicon substrate. For reference, a unit pixel region (Micro pixel, MP) of the silicon photoexposure device 10 can be divided by a trench surrounding the micro pixels. That is, the trenches disposed on the left and right sides and the trenches disposed on the front and rear sides can surround the micro-pixel region.

Next, FIG. 3B is a cross-sectional view showing a cross section of a silicon light diffusing device using a diffusion preventing layer according to an embodiment of the present invention.

3B, the silicon light scattering device 10 according to an embodiment of the present invention includes a substrate 110, an intermediate layer 120, a trench 130, a P-type semiconductor layer 140, an N-type semiconductor Layer 150, an insulating layer 160, a polysilicon resistive layer 170, a metal electrode 180, and a diffusion barrier layer 190.

The intermediate layer 120 may be formed on the substrate 110. Further, the substrate 110 may be doped with a p-conductivity type or an n-conductivity type, and may be a silicon substrate. At this time, the doping concentration of the substrate may be a high concentration of 10 ¹⁶ to 10 ²⁰ cm ^-3 , or may be a low concentration of 10 ¹² to 10 ¹⁶ cm ^-3 to reduce a naturally occurring dark current.

The intermediate layer 120 is formed between the top of the substrate 110 and the insulating layer 160. At this time, the intermediate layer 120 may be formed using an epitaxy process. Further, the trench 130 and the PN junction layer may be formed on the intermediate layer 120.

In addition, the intermediate layer 120 is doped with the same conductivity type as the substrate 110. That is, if the substrate 110 is of the p-conductivity type, the intermediate layer 120 is also of the p-conductivity type. The intermediate layer 120 may have a doping concentration different from that of the substrate 110, such as 1014 to 1018 cm -3, and may have a doping concentration of 10 ¹² to 10 ¹⁶ cm -3 to reduce the dark current naturally occurring on the substrate 110. ^-3 may be formed at the same doping concentration as the substrate 110.

The trenches 130 may be formed in the intermediate layer 120. In addition, the silicon photodiode element 10 can be divided into the unit micro-pixel regions through the trenches 130. [

For reference, a PN junction layer is grown in the intermediate layer 120 by the P-type semiconductor layer 140 and the N-type semiconductor layer 150, and a PN junction is formed to form a depletion region. The electric field discharge generated in this depletion region is closely related to the amplification of the light incident on the micro-pixel. That is, a secondary photon can be generated, and a crosstalk phenomenon adversely affecting the photodetecting efficiency of the micropixel can be caused by the generated secondary photon. In order for the light incident on the micro-pixel to be amplified, incident light must be efficiently transmitted to the PN junction layer.

The insulating layer 160 may isolate multiple pixels in the silicon photodiode element 10. [ The insulating layer 160 may also be formed between the intermediate layer 120 and the trench region to form a trench 130 together with the PN junction layer 130 before the trench 130 is filled with oxide, An insulating layer 160 may be formed on a region other than the trench 130 to isolate multiple pixels.

On the other hand, when light (photon) is incident through the insulating layer 160, electron-hole pairs generated by light are accelerated by the internal magnetic field, so that impact ionization causes the number of carriers Signals can be amplified and displayed while increasing exponentially. Light (photons) may also be incident through the polysilicon resistive layer 170.

In addition, the polysilicon resistive layer 170 may be formed on the upper surface of the insulating layer 160. At this time, when avalanche breakdown is caused by the light incident into the micro-pixels of the silicon photo-resist device 10 due to quenching resistance, the polysilicon resistive layer 170 shields the current after a certain amount of current flows, By making the amount of current output from all the micro-pixels within the multiplication element 10 the same and ending the residual current within the micro-pixel, the micro-pixel can be put into operation within tens of nanoseconds.

A metal electrode 180 connecting the polysilicon resistance layer 170 and the PN junction layer may be formed in the silicon light diffusing device 10. The metal electrode 180 may include a PN junction layer and a polysilicon resistance layer 170 can be electrically connected.

On the other hand, the diffusion preventing layer 190 prevents the impurity from diffusing to the trench 130 in the subsequent heat treatment process after the impurity implantation in the PN region. In the conventional configuration, when the impurity is diffused to the trench 130, it has an electric field value larger than the planar region of the PN junction at the upper and tapered surfaces of the trench 130 and the corner portion, so that the PN breakdown voltage of the sensor The problem could be reduced.

However, the diffusion barrier layer 190 according to an embodiment of the present invention prevents diffusion of impurities to the trench 130, thereby preventing the PN breakdown voltage of the sensor from being reduced.

At this time, the diffusion preventing layer 190 may be formed of silicon nitride (Si 3 N 4) formed by implanting nitrogen ions between the sidewalls of the trenches 130 and the PN junction layer, followed by heat treatment.

Next, referring to FIG. 4, a manufacturing method of a silicon light diffusing device will be described in detail.

4 is a flowchart illustrating a fabrication process of a silicon light diffusing device using a diffusion preventing layer according to an embodiment of the present invention.

A method of manufacturing a silicon photoemission device using a diffusion barrier layer according to an embodiment of the present invention includes forming an intermediate layer 120 on a substrate 110 at step S400 and forming a trench 130 A diffusion barrier layer 190 is formed between the PN junction layer and the sidewall of the trench 130 at step S430 to form a PN junction layer in the micro-pixel region at step S430, The polysilicon resistance layer 170 is formed on the upper surface of the insulating layer 160 in step S450 and the polysilicon resistance layer 170 is formed on the upper surface of the polysilicon resistance layer 170 in step S440. And the PN junction layer is formed (S460).

FIG. 5 is a view illustrating a fabrication process of a silicon light diffusion device using a diffusion prevention layer according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 5A, an intermediate layer 120 is formed on a substrate 10 (S400).

For example, the substrate 110 may be doped with a high concentration of 10 ¹⁶ to 10 ²⁰ cm ^-3 doped with a p-conductivity type or n-conductivity type, or may be doped with a dark current naturally occurring in the substrate 110 ) May be performed at a low concentration of 10 ¹² to 10 ¹⁶ cm ^-3 .

Next, as shown in FIG. 5B, a trench 130 separating the unit micro-pixels is formed in the element in which the intermediate layer 120 is formed in step S400 (S410).

At this time, the trench 130 separating the unit micro-pixels may be formed by filling the interior of the trench 130 with oxide.

On the other hand, the silicon diffraction element 10 includes a plurality of regions of micro-pixels, and the unit micro-regions may be separated by the trenches 130 surrounding the micro-pixels.

In addition, the trenches 130 may be formed by forming an insulating layer 160 for pixel isolation together. Silicon dioxide or silicon nitride may be used as the insulator used at this time.

Next, as shown in FIG. 5C, the P-type semiconductor layer 140 and the N-type semiconductor layer 150 are formed on the element formed in the preceding step S410, and the PN junction layer (S420).

That is, the PN junction layer may be formed in the intermediate layer 120 region. The PN junction layer may be formed using an ion implantation process. Then, a depletion region is formed due to the PN junction.

Next, as shown in FIG. 5D, a diffusion preventing layer 190 is formed between the PN junction layer formed in the preceding step S420 and the sidewalls of the trench 130 (S430).

At this time, the diffusion preventing layer 190 can prevent the impurity from diffusing to the trench 130 in the subsequent heat treatment process after the impurity is implanted into the PN region.

Also, the diffusion preventing layer 190 may be formed by ion implanting nitrogen. Then, silicon nitride (Si ₃ N ₄ ) can be formed by bonding with silicon through a heat treatment process. A more detailed method will be described with reference to FIG. 6, which will be described later.

Next, as shown in FIG. 5E, the insulating layer 160 is formed on the upper surface of the silicon photoresist 10 formed in the previous step S430 (S440).

At this time, the insulating layer 160 may be made of silicon dioxide or silicon nitride as an insulator for isolating the pixels. When a photon is incident on the PN junction layer through the insulating layer 160, an electron-hole pair is generated, As acceleration is accelerated, electrical breakdown can occur by impact ionization.

Next, as shown in FIG. 5F, the polysilicon resistance layer 170 may be formed on the upper surface of the insulating layer 160 formed in the preceding step S440 (S450).

According to an embodiment of the present invention, a polysilicon resistive layer 170 may be formed on the upper surface of the insulating layer 160, and then an insulating layer 160 may be further filled on the polysilicon resistive layer 170 have. As the insulating layer 160 is deposited, light reflected from the light incident on each micro-pixel can be reduced to improve sensitivity.

Next, as shown in FIG. 5G, the metal electrode 180 connecting the polysilicon resistance layer 170 formed in the preceding step S450 and the PN junction layer is formed (S460).

The step of forming the metal electrode 180 may include forming a contact hole for electrically connecting the polysilicon resistance layer 170, the PN junction layer, and the metal electrode 180 to each other through the insulating layer 160 Step < / RTI >

A photoresist is laminated on the upper surface of the polysilicon resistive layer 170 and the insulating layer 160 to form a contact hole, a specific portion is exposed using a mask, the pattern is developed in the shape of the intended contact hole, The polysilicon resistive layer 170 and the insulating layer 160 may be etched by wet etching or dry etching.

That is, the contact hole can be formed by exposing a part of the PN junction layer by etching the polysilicon resistance layer 170 and the insulating layer 160. At this time, since the metal electrode 180 is disposed on the contact hole, the polysilicon resistance layer 170 and the PN junction layer can be electrically connected.

Meanwhile, according to the embodiment, the diffusion barrier layer 190 may be formed first (S430) before the step S420 of forming the PN junction layer in the region of the micro-pixels.

Referring to FIG. 6, FIG. 6 is a flowchart illustrating a fabrication process of a silicon light diffusing device according to another embodiment of the present invention.

Referring to FIG. 6, a method of fabricating a silicon photoemission device using a diffusion barrier layer according to an embodiment of the present invention includes forming an intermediate layer 120 on a substrate 110 (S600) A diffusion preventing layer 190 is formed adjacent to the sidewall of the trench 130 at step S620 and a diffusion preventing layer 190 is formed between the diffusion preventing layers 190 included in the micro- A PN junction layer is formed in step S630 and an insulating layer 160 is formed on the upper surface of the silicon photodevice element 10 in step S640 and a polysilicon resistance layer 170 is formed on the upper surface of the insulating layer 160 (S650). Then, the metal electrode 180 connecting the polysilicon resistance layer 170 and the PN junction layer is formed (S660).

Meanwhile, FIG. 7 is a view for explaining a process of a diffusion preventing layer according to an embodiment of the present invention.

7, the diffusion barrier layer 190 prevents diffusion of impurities in the PN region to the sidewalls of the trench 130, thereby reducing the PN breakdown voltage in the sidewall region of the trench 130 Can be prevented.

To form the diffusion preventing layer 190, a photoresist 200 is laminated on the upper surface of the PN junction layer, a specific portion is exposed using a mask, and then the pattern is developed. At this time, a specific portion is between the PN junction layer and the sidewall of the trench 130, which is apart from the PN junction layer and can be in contact with the insulating layer 160 on the side wall of the trench 130. Thereafter, nitrogen ions are injected and then heat treatment is performed. Then, the injected nitrogen is combined with silicon in the intermediate layer 120 to form silicon nitride (Si 3 N 4), and unnecessary photoresist 200 is formed in an organic Removing it with a solvent, or performing a dry or wet etching process.

According to an embodiment of the present invention, a PN junction layer is first formed on the intermediate layer 120 and a unit micro-pixel is formed on the intermediate layer 120 before the trench 130 separating the unit micro- The trench 130 can be formed.

Next, FIG. 8 is a flowchart illustrating a fabrication process of a silicon light diffusing device according to another embodiment of the present invention.

Referring to FIG. 8, a method of manufacturing a silicon photoemissive device according to another embodiment of the present invention includes forming an intermediate layer 120 on a substrate 110 (S800), forming a PN A diffusion preventing layer 190 is formed between the PN junction layer and the sidewalls of the trench 130 to form a trench 130 for forming a junction layer (S810) An insulating layer 160 is formed on the upper surface of the silicon light diffusing device 10 in step S840 and a polysilicon resistive layer 170 is formed on the upper surface of the insulating layer 160 S850), a metal electrode 180 connecting the polysilicon resistance layer 170 and the PN junction layer is formed (S860).

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

10: Silicone diffraction element
110: substrate
120: middle layer
130: trench
140: P-type semiconductor layer
150: N-type semiconductor layer
160: insulating layer
170: Polysilicon resistance layer
180: metal electrode
190: diffusion prevention layer
200: photoresist

Claims (12)

A manufacturing method of a silicon light diffusing device using a diffusion preventing layer,
Forming a trench for separating the unit micro-pixels from the intermediate layer;
Forming a PN junction layer in a region of the micro-pixel;
Forming a diffusion barrier layer between the PN junction layer and the sidewalls of the trench;
Forming an insulating layer on an upper surface of the silicon light diffusing device;
Forming a polysilicon resistive layer on an upper surface of the insulating layer; And
And forming a metal electrode connecting the polysilicon resistance layer and the PN junction layer. The method according to claim 1,
The step of forming the diffusion barrier layer
Wherein the silicon nitride (Si ₃ N ₄ ) is formed by injecting nitrogen ions between the sidewalls of the trench and the PN junction layer and then performing heat treatment. The method according to claim 1,
The diffusion barrier layer
Thereby preventing impurities of the PN junction layer from diffusing to the sidewalls of the trench and preventing a PN breakdown voltage from decreasing in a sidewall region of the trench. . In a silicon light diffusing element using a diffusion preventing layer,
Board;
An intermediate layer on the substrate;
A trench formed in the intermediate layer and defining a region of the unit micro-pixels;
A PN junction layer formed on the intermediate layer;
A diffusion barrier layer formed between the PN junction layer and the sidewalls of the trench;
An insulating layer formed on an upper surface of the silicon light-scattering element;
A polysilicon resistance layer formed on an upper surface of the insulating layer;
And a metal electrode connecting the polysilicon resistance layer and the PN junction layer. 5. The method of claim 4,
The diffusion barrier layer
Wherein the silicon nitride (Si ₃ N ₄ ) is formed by injecting nitrogen ions between the sidewalls of the trench and the PN junction layer and then heat-treating the silicon nitride superlattice. 5. The method of claim 4,
The diffusion barrier layer
Wherein the PN junction layer prevents impurities in the PN junction layer from diffusing to the sidewalls of the trench to prevent a PN breakdown voltage from decreasing in a sidewall region of the trench. A manufacturing method of a silicon light diffusing device using a diffusion preventing layer,
Forming a trench for separating the unit micro-pixels from the intermediate layer;
Forming a diffusion barrier layer adjacent the sidewalls of the trench;
Forming a PN junction layer between the diffusion preventing layers included in the region of the micro-pixel;
Forming an insulating layer on an upper surface of the silicon light diffusing device;
Forming a polysilicon resistive layer on an upper surface of the insulating layer; And
And forming a metal electrode connecting the polysilicon resistance layer and the PN junction layer. 8. The method of claim 7,
The step of forming the diffusion barrier layer
Wherein the silicon nitride (Si ₃ N ₄ ) is formed by injecting nitrogen ions between the sidewalls of the trench and the PN junction layer and then performing heat treatment. 8. The method of claim 7,
The diffusion barrier layer
Thereby preventing impurities of the PN junction layer from diffusing to the sidewalls of the trench and preventing a PN breakdown voltage from decreasing in a sidewall region of the trench. . A manufacturing method of a silicon light diffusing device using a diffusion preventing layer,
Forming a PN junction layer in an area set as a micro-pixel of the intermediate layer;
Forming a trench for dividing an intermediate layer formed with the PN junction layer into unit micro-pixels;
Forming a diffusion barrier layer between the PN junction layer and the sidewalls of the trench;
Forming an insulating layer on an upper surface of the silicon light diffusing device;
Forming a polysilicon resistive layer on an upper surface of the insulating layer; And
And forming a metal electrode connecting the polysilicon resistance layer and the PN junction layer. 11. The method of claim 10,
The step of forming the diffusion barrier layer
Wherein the silicon nitride (Si ₃ N ₄ ) is formed by injecting nitrogen ions between the sidewalls of the trench and the PN junction layer and then performing heat treatment. 11. The method of claim 10,
The diffusion barrier layer
Thereby preventing impurities of the PN junction layer from diffusing to the sidewalls of the trench and preventing a PN breakdown voltage from decreasing in a sidewall region of the trench. .

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