KR20150063882A - Silicon photomultiplier and manufacturing method thereof - Google Patents

Abstract

According to an aspect of the present invention, there is provided a method of manufacturing a silicon photoemission device, comprising: providing a substrate having a plurality of trenches and a gap filler for dividing a unit micro-pixel region; Forming a PN junction layer in each micro-pixel region; Depositing a thin film of light incident on the top surface of the substrate; Forming a contact hole for contacting the PN junction layer of the micro-pixel region in the light incidence thin film; Depositing an oxide film on the light incident portion thin film to fill the contact hole with the oxide film; And removing the oxide film to form a rounded spacer on a sidewall of the contact hole.

Description

TECHNICAL FIELD [0001] The present invention relates to a silicon photocatalytic pipe device,

The present invention relates to a method of manufacturing a silicon photo-multiplier device (SiPM).

Silicon Photomultiplier (SiPM), which is designed to replace existing PMT (Photomultiplier) in the optical sensor field, can be manufactured in a very small size and operates at very low voltage at room temperature (usually 25 ~ 100V), and is not affected by the magnetic field. In addition, the silicon photodiode can amplify the signal by a factor of 10,000 times, allowing measurement of a single photon and obtaining a bright image even in a dark room.

Fig. 1 is a view showing a general silicon opto-electronic device and any one of the micro-pixels included therein, Fig. 2 is a cross-sectional view of a micro-pixel of Fig. 1 corresponding to a doping concentration of each of the first and second junction layers and the epitaxial layer And shows the electric field distribution of the active region with application of the operating voltage.

As shown in FIG. 1, the silicon photoresist pipeline device 100 includes a plurality of micro-pixels 110. The size of each micro-pixel 110 is 10 to 100 μm, and 100 to 1000 micro-pixels per 1 mm 2 of area are accumulated. Each micro-pixel 110 includes an epitaxial layer 130 of a p-conductive type formed to a thickness of 5 탆 or less on a substrate 140 of a p + conductivity type, and an epitaxial layer 130 sequentially formed in the epitaxial layer 130 and a PN junction layer (PN junction layer) 120 formed by implanting p ions and n + ions.

The simple operation principle of the micro-pixel 110 is as follows. In the PN junction layer 120, a very depletion region is formed as a very strong electric field is formed from the n-type to the p-type. 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 110 is formed. This accelerated electron-hole pair causes an Avalanche Breakdown, and the signal is amplified by the electric field discharge. Each micro-pixel 110 operates in the Geiger mode shown in FIG. 2, and a plurality of amplified signals are combined into one output. 2 is a diagram showing the distribution of the electric field in the epitaxial layer in a general silicon photocatalytic pipe element.

This conventional silicon photocatalytic pipe element 100 includes a trench structure and a guard ring disposed between the micro-pixels 110 to optically separate each micro-pixel 110 from each other. That is, the trench structure and the guard ring are configured to reduce mutual influence between the micro-pixels 110.

On the other hand, Korean Patent No. 10-1113364 (entitled "Silicon Photomultiplier Tubes and Cells for the Silicon Photomultiplier Tubes") discloses a structure of a conventional silicon photomultiplier tube and is formed between micropixels by anisotropic etching Describes a technique for a recessed separating element.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a silicon light amplifier device capable of minimizing a pinch-off phenomenon occurring in a contact hole of the silicon light amplifier device.

According to a first aspect of the present invention, there is provided a method of manufacturing a silicon photoemissive device, comprising: providing a substrate having a plurality of trenches for dividing a unit micro- ; Forming a PN junction layer in each micro-pixel region; Depositing a thin film of light incident on the top surface of the substrate; Forming a contact hole for contacting the PN junction layer of the micro-pixel region in the light incidence thin film; Depositing an oxide film on the light incident portion thin film to fill the contact hole with the oxide film; And removing the oxide film to form a rounded spacer on a sidewall of the contact hole.

According to a second aspect of the present invention, there is provided a silicon photodissociation element comprising: a substrate having a plurality of trenches and trenches for defining a unit micro-pixel area and having a gap fill; a PN junction layer formed on the unit micro- A contact hole formed in the thin film, a rounded spacer formed on a sidewall of the contact hole, and a contact in contact with the PN junction layer through the contact hole.

According to the above-described constitution of the present invention, the pinch-off phenomenon occurring in the contact portion of the silicon optoelectronic device can be minimized. By minimizing the pinch-off phenomenon, it is possible to sufficiently bring the metal and the PN junction into contact with each other and improve the yield of the micro-pixels in the silicon photo-multiplier device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a general silicon opto-electronic device and any one of micro-pixels included therein. FIG.
Fig. 2 is a diagram showing the electric field distribution of the active region according to application of operating voltage, corresponding to the doping concentration of each of the first and second junction layers and the epitaxial layer in the micro-pixel of Fig. 1;
FIG. 3 is a cross-sectional view showing a cross section of a silicon light diffusing device to which the present invention is applied.
4 is a diagram showing a concept of a problem and a solution to be solved by the present invention.
FIGS. 5 and 6 are views showing a process of manufacturing a silicon light diffusing device according to an 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.

FIG. 3 is a cross-sectional view showing a cross section of a silicon light diffusing device to which the present invention is applied.

The illustrated silicon light diffraction element 10 includes a plurality of trenches 102 and 104 for delimiting a micro-pixel area in a substrate 10, a gap fill 110 and 112 filling each trench, An N-type semiconductor layer 122 and an N-type semiconductor layer 120. An insulating layer 124 is formed on the N-type semiconductor layer 120. The light incident portion A thin film 126, and a contact 130 in contact with the N-type semiconductor layer 120.

At this time, in the case of the contact hole of the silicon light-scattering device 10 manufactured according to a conventional process, a pinch-off phenomenon occurs near the edge.

4 is a diagram showing a concept of a problem and a solution to be solved by the present invention.

(a), in the case of a contact of a silicon photoemissive device fabricated according to a general process, a pinch off phenomenon occurs at the edge or edge of the contact hole (indicated by a dotted circle) Can be confirmed. This is a phenomenon that occurs due to insufficient deposition of metal to the corner portion in the metal deposition process because the bottom edge of the contact hole according to a typical method of forming a contact hole has the same rectangular structure. This may result in insufficient contact between the metal and the PN junction, thereby reducing the yield of the micro-pixel in the overall sensor.

In order to solve this problem, it is possible to consider a method of depositing a large amount of metal to reach the edge of the metal. For this purpose, it is necessary to form the light incident thin film 126 thick, There is a problem that the etching process can withstand the process.

 Thus, in the present invention, as shown in (b), a round-shaped spacer is formed on the sidewall of the contact hole, and then a contact generating process is performed.

According to such a process, it is possible to sufficiently connect the metal and the PN junction without performing a process of increasing the amount of metal in forming the contact.

Detailed processes will be described with reference to the drawings.

FIGS. 5 and 6 are views showing a process of manufacturing a silicon light diffusing device according to an embodiment of the present invention.

First, as shown in FIG. 5A, a substrate 200 on which a trench and a trench for defining a unit micro-pixel region 220 are formed is provided with a gap fill 210 and 212, Type semiconductor layer 222 and the N-type semiconductor layer 224 are formed, and a PN junction layer is formed in the unit micro-pixel region 220.

At this time, the substrate 200 has the epitaxial layer 204 formed on the silicon substrate 202.

For example, the silicon substrate 202 may be doped with a high concentration of 10 ¹⁷ 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 silicon substrate 202 Low current doping of 10 ¹² to 10 ¹⁶ cm ^-3 may be used to reduce the dark current.

The epitaxial layer 204 is doped with the same conductive type as the silicon substrate 202. That is, if the silicon substrate 202 is of the p conductivity type, the epitaxial layer 204 is also of the p conductivity type. The epitaxial layer 204 can be formed at a doping concentration different from that of the silicon substrate 202, such as 10 ¹⁴ to 10 ¹⁸ cm ^-3, and the dark current naturally occurring in the silicon substrate 202 can be reduced The doping concentration may be the same as that of the silicon substrate 202, such as 10 ¹² to 10 ¹⁶ cm ^-3 .

On the other hand, the PN junction layer is grown in the epitaxial layer 204, and a PN junction occurs to form a depletion region. A secondary photon can be generated by the electron scattering generated in the depletion region, and a crosstalk phenomenon which adversely affects the photodetecting efficiency of the micropixel can be caused by the generated secondary photon.

Generally, the PN junction layer is 10 ¹⁷ ~ 10 ¹⁸ cm ^{- 3} is formed by doping concentration silicon substrate 202 and the first conductive layer 222 of the same conductivity type ^{and, 10 19 ~ 10 21 cm -} 3 The doping concentration of the And a second conductive layer 204 of a conductive type opposite to the silicon substrate 202.

On the other hand, the silicon photodiode element includes a plurality of micro-pixel areas, and the unit micro-pixel area 220 includes two gap pills 210 and 212 arranged on the left and right sides and two gap pills (not shown) . ≪ / RTI >

5 (b), a light incident portion thin film 226 is laminated on the upper surface of the substrate 200, and a contact hole 228 is formed. As the light incident thin film 226, a polysilicon resistance may be used. On the other hand, a contact hole 228 is formed to expose each PN junction layer for each micro-pixel region. A photoresist is stacked on the upper surface of the light incident portion thin film 226 to form a contact hole 228, and a specific portion is exposed using a mask, and then the photoresist and the light incident thin film The step of etching the first insulating layer 226 may be performed.

On the other hand, according to the embodiment, it is possible to further laminate an insulating layer on the PN junction layer before lamination of the light incidence portion thin film 226. [ The sensitivity can be improved by reducing the light reflected from the light incident on each micro-pixel according to the deposition of the insulating layer. In this case, the insulating layer and the light incidence thin film 226 are etched to form the contact hole 228.

Next, as shown in FIG. 6C, an oxide film 230 is stacked to form a spacer on the side wall of the contact hole 228. Thus, the oxide film 230 fills the contact holes 228.

Next, as shown in FIG. 6 (d), the oxide film 230 is removed, and the contact hole 228 is etched to form the spacer 232. At this time, round-type spacers 232 are formed by etching using anisotropic etching.

Next, although not shown, a round-shaped spacer 232 is filled with a metal for the contact hole provided in the side wall, and a contact is formed. According to such a process, the problem of the pinch-off phenomenon that may occur in forming a contact can be solved.

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.

200: substrate 202: silicon substrate
204: epitaxial layer 210, 212:
222: P-type semiconductor layer 224: N-type semiconductor layer
226: light incidence thin film 228: contact hole
230: oxide film 232: spacer

Claims (7)

A method of manufacturing a silicon photoresist piping element,
Forming a plurality of trenches on the substrate to separate unit micro-pixel areas;
Depositing an oxide on the substrate on which the trench is formed to gap fill the trench;
Removing the oxide for an area other than the area of the captured trench;
Depositing a protective film on the entire surface of the substrate from which the oxide has been removed in a region excluding the region of the trench; And
And etching the passivation layer to form a spacer at an edge portion of the oxide formed on the trench. The method according to claim 1,
Wherein forming the spacers comprises:
Wherein the protective film is etched to leave a part of the protective film on an edge portion of the oxide formed on the trench. The method according to claim 1,
Wherein the protective film is silicon nitride. The method according to claim 1,
Wherein removing the oxide comprises:
Removing the oxide through a photoresist mask in regions other than the regions of the captured trenches. The method according to claim 1,
After the step of forming the spacer,
Forming a PN junction layer in each micro-pixel region;
Depositing a thin film of light incident on the top surface of the substrate;
And forming a contact for contacting the PN junction layer of the micro-pixel region on the light incidence thin film. In a silicon light pipe device,
A substrate on which a plurality of trenches are formed to define a unit micro-pixel area, an oxide is gap-filled on each trench,
A spacer formed on an edge portion of the oxide formed on the trench;
A PN junction layer formed on top of each of the micro pixel regions;
A light incident thin film formed on the upper surface of the PN junction layer; And
And a contact formed on the light incidence thin film so as to be in contact with the PN junction layer. The method according to claim 6,
Wherein the spacer is silicon nitride.

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