KR20230052077A - Photodetector with improved absorption efficiency for detecting long-wavelength infrared, and manufacturing method of the same - Google Patents

Abstract

A photodetector for detecting far-infrared rays according to one embodiment of the present invention includes: an absorption layer for absorbing far-infrared rays; a waveguide mode layer including a plurality of waveguide elements arranged in a periodic structure on one side of the absorption layer to propagate incident far-infrared rays to the absorption layer; and a reflective layer disposed on the other side of the absorption layer to reflect far-infrared rays incident from the absorption layer.

Description

Photodetector with improved absorption efficiency for far-infrared detection and manufacturing method thereof

The present invention relates to a photodetector and a method for manufacturing the same, and more particularly, to a photodetector (PD) with improved absorption efficiency for detecting long-wavelength infrared (LWIR) rays and a method for manufacturing the same.

Light sensing is applied to various sensing fields. In general, compared to mid-wavelength infrared (MWIR), far-infrared is not only advantageous for detecting low-temperature targets, but is not absorbed in the atmosphere, penetrates fog, clouds, smoke, etc., and can detect objects behind bright light. It is also useful for detection. For this reason, in recent years, studies have been conducted to detect low-temperature targets using far-infrared rays. For example, a technology for detecting a low-temperature target using far-infrared rays can be applied to military search, tracking, surveillance, and reconnaissance.

For far-infrared detection, photodetectors require a thick absorbing layer. However, as the absorber layer is thicker, strain may accumulate in the absorber layer, resulting in defects, which may degrade the performance of the photodetector. In addition, when the photodetector is applied to a camera type, it is difficult to integrate the photodetector.

The technical problem to be solved by the present invention is to provide a photodetector with improved absorption efficiency for detecting far-infrared rays that can be thinned without performance deterioration and a manufacturing method thereof.

An optical detector for detecting far-infrared rays according to an embodiment of the present invention includes an absorption layer for absorbing far-infrared rays, and a plurality of waveguide elements arranged in a periodic structure on one surface of the absorption layer to propagate incident far-infrared rays to the absorption layer. and a reflective layer disposed on the other side of the absorbing layer to reflect far-infrared rays incident from the absorbing layer.

The absorption layer may absorb far-infrared rays incident through openings between the plurality of waveguide elements, far-infrared rays propagated from the plurality of waveguide elements, and far-infrared rays reflected from the reflection layer.

The plurality of waveguide elements may be made of a material having a refractive index higher than that of air.

The plurality of waveguide elements may be made of a silicon material.

The reflective layer may be made of a metallic material.

The absorption layer may include a first n-type electrode layer coupled to the waveguide mode layer, a second n-type electrode layer disposed on the reflective layer, an active layer disposed between the first n-type electrode layer and the second n-type electrode layer, and the active layer. and a barrier layer disposed between the second n-type electrode layer.

The photodetector for detecting far-infrared rays may further include a substrate coupled to the reflective layer to support the reflective layer, the absorbing layer, and the waveguide mode layer.

The substrate may include a readout integrated circuit for detecting absorbed far infrared rays.

The waveguide mode layer is divided into a plurality of period units defined around each of the plurality of waveguide elements, and the size of the waveguide mode layer is the width of each of the plurality of period units, the width of each of the plurality of waveguide elements, and the size of the waveguide mode layer. It is defined as the height of each of the plurality of waveguide elements, and the width of each of the waveguide elements may be determined such that an absorption spectrum area for each of the plurality of period units is maximized.

A method of manufacturing a photodetector for detecting far-infrared rays according to another embodiment of the present invention includes preparing an absorption layer for absorbing far-infrared rays, combining the absorption layer on a reflection layer for reflecting far-infrared rays incident from the absorption layer, and and forming a waveguide mode layer on the absorption layer including a plurality of waveguide elements arranged in a periodic structure on the absorption layer to propagate incident far-infrared rays to the absorption layer.

The absorption layer may absorb far-infrared rays incident through openings between the plurality of waveguide elements, far-infrared rays propagated from the plurality of waveguide elements, and far-infrared rays reflected from the reflection layer.

The plurality of waveguide elements may be made of a material having a refractive index higher than that of air.

The plurality of waveguide elements may be made of a silicon material.

The reflective layer may be made of a metallic material.

The combining of the absorption layer on the reflective layer may include forming a first reflective layer on the absorbing layer, forming a second reflective layer on a substrate, and inverting the first reflective layer onto the second reflective layer such that the absorbing layer is inverted. It may include forming the reflective layer by combining with.

The step of preparing the absorber layer includes forming the absorber layer on the donor substrate, and the step of bonding the absorber layer on the reflective layer includes removing the donor substrate from the absorber layer bonded on the reflective layer. may further include.

Forming the absorption layer on the donor substrate may include forming a first n-type electrode layer on the donor substrate, forming an active layer on the first n-type electrode layer, and forming a barrier layer on the active layer. and forming a second n-type electrode layer on the barrier layer.

The waveguide mode layer is divided into a plurality of period units defined around each of the plurality of waveguide elements, and the size of the waveguide mode layer is the width of each of the plurality of period units, the width of each of the plurality of waveguide elements, and the size of the waveguide mode layer. It is defined as the height of each of the plurality of waveguide elements, and the width of each of the waveguide elements may be determined such that an absorption spectrum area for each of the plurality of period units is maximized.

According to embodiments of the present invention, a photodetector may have improved absorption efficiency for far infrared ray detection. At this time, the absorption layer may have an improved absorption rate with the help of the waveguide mode layer and the reflection layer. For this reason, even if the thickness of the absorption layer is thin, the absorption layer can absorb a sufficient amount of far-infrared rays. Accordingly, a thin film photodetector for detecting far-infrared rays can be implemented without performance degradation.

In addition, the photodetector may detect far-infrared rays of a more extended wavelength band. In this case, the photodetector can detect far-infrared rays of a more extended wavelength band with a remarkably low signal-to-noise ratio. Accordingly, the photodetector may have improved absorption efficiency for far-infrared rays of a more extended wavelength band.

1 is a side view illustrating a photodetector for detecting far-infrared rays according to an embodiment of the present invention.
2 is a perspective view illustrating a photodetector for detecting far-infrared rays according to an embodiment of the present invention.
3 is a cross-sectional view showing a photodetector for detecting far-infrared rays according to an embodiment of the present invention.
4 to 6 are graphs for explaining performance of a photodetector according to an embodiment of the present invention.
7 is a flowchart illustrating a method of manufacturing a photodetector according to an embodiment of the present invention.
8 to 12 are cross-sectional views illustrating a method of manufacturing a photodetector according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, throughout the specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

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

1 is a side view illustrating a photodetector for detecting far-infrared rays according to an embodiment of the present invention.

Referring to FIG. 1 , an optical detector 100 according to an embodiment of the present invention is for detecting far infrared rays and may include an absorption layer 110, a waveguide mode layer 120, and a reflection layer 130. Compared to mid-infrared rays, far-infrared rays are not only advantageous for detecting low-temperature targets, but also advantageous for atmospheric environments such as not being absorbed in the atmosphere and penetrating fog, clouds, and smoke well, and also for detecting objects behind bright light. It is advantageous. Here, the far-infrared ray may have a wavelength range of 7 μm to 12 μm, preferably a wavelength range of 8 μm to 10 μm.

The absorption layer 110 may absorb far infrared rays to be detected. In this case, as far-infrared rays absorbed by the absorption layer 110 are detected, a target (object) may be detected based on a light absorption spectrum of the far-infrared rays. According to one embodiment, the absorption layer 110, as described later with reference to FIGS. 2 and 3, may be implemented with an nBn structure.

The waveguide mode layer 120 may be disposed on one surface of the absorption layer 110 . In other words, the waveguide mode layer 120 may be disposed on the absorption layer 110 and may be disposed on a path of far-infrared rays incident on the absorption layer 110 in the air. The top of the absorbing layer 110 means a top on a plane formed by the absorbing layer 110, and may mean a third direction (z). Hereinafter, a plane means a plane formed by a first direction (x) and a second direction (y) orthogonal to the first direction (x), and the third direction (z) is the first direction (x) and the second direction (x) It means the direction perpendicular to the plane formed by (y).

The guided-mode layer 120 may provide guided-mode resonance (GMR) absorption for the absorption layer 110 . To this end, the waveguide mode layer 120 may include a plurality of waveguide elements 121 . The plurality of waveguide elements 121 may be arranged in a periodic structure on one surface of the absorption layer 110 . Also, an opening 123 may be provided between the plurality of waveguide elements 121 . In this case, the guiding mode layer 120 may be divided into a plurality of period units defined around each of the guiding elements 121 . The plurality of waveguide elements 121 may propagate far-infrared rays incident to the waveguide elements 121 in the air to the absorption layer 110 . At this time, the waveguide element 121 may not only transmit incident far infrared rays but also diffract them and propagate them to the absorption layer 110 . Through this, based on far-infrared rays propagating from the plurality of waveguide elements 121 and far-infrared rays incident from the air through the openings 123, waveguide mode resonance absorption may occur in the absorption layer 110. Here, the plurality of waveguide elements 121 may be made of a material having a high refractive index, that is, a refractive index higher than the refractive index of the atmosphere and similar to that of the absorption layer 110 . Also, the plurality of waveguide elements 121 may be made of a dielectric material. For example, the plurality of waveguide elements 121 may be made of a silicon (Si) material, and the refractive index of the silicon material may be about 3.6.

The reflective layer 130 may be disposed on the other side of the absorbing layer 110 . That is, the reflective layer 130 may be disposed below the absorbing layer 110 . The reflective layer 130 may be disposed on the opposite side of the waveguide mode layer 120 with the absorbing layer 110 interposed therebetween. The reflective layer 130 may provide Fabry-Perot resonant absorption to the absorbing layer 110 . That is, the reflective layer 130 may reflect far-infrared rays incident on the reflective layer 130 from the absorbing layer 110 . Through this, Fabry-Perot resonance absorption may occur in the absorbing layer 110 based on far-infrared rays reflected by the reflective layer 130 . The reflective layer 130 may be made of a high reflectance metal material.

As such, the absorption layer 110 absorbs far infrared rays incident through the openings 123 between the plurality of waveguide elements 121, far infrared rays propagated from the plurality of waveguide elements 121, and far infrared rays reflected from the reflection layer 130. can do. In this case, the absorption layer 110 may absorb far-infrared rays incident through the opening 123 and far-infrared rays propagating from the plurality of waveguide elements 121 through waveguide mode resonance absorption. Also, the absorption layer 110 may absorb far-infrared rays reflected from the reflective layer 130 through Fabry-Perot resonance absorption. Accordingly, the absorption layer 110 may have an improved absorption rate with the help of the waveguide mode layer 120 and the reflection layer 130 . For this reason, even if the thickness of the absorption layer 110 is thin, the absorption layer 110 can absorb a sufficient amount of far infrared rays.

2 is a perspective view illustrating a photodetector for detecting far-infrared rays according to an embodiment of the present invention. 3 is a cross-sectional view showing a photodetector for detecting far-infrared rays according to an embodiment of the present invention.

Referring to FIGS. 2 and 3 , the photodetector 100 according to an embodiment of the present invention may include an absorption layer 110, a waveguide mode layer 120, a reflection layer 130, and a substrate 240. Here, since the absorption layer 110, the waveguide mode layer 120, and the reflection layer 130 include the same features as those described above with reference to FIG. 1, overlapping descriptions are omitted. In this case, the waveguide mode layer 120 is divided into a plurality of period units, and the period units may be defined around each of the plurality of waveguide elements 121 . That is, one of the plurality of waveguide elements 121 may be disposed in each period unit.

The size of the waveguide mode layer 120 may be defined as a width in the first direction (x) and a height in the third direction (z). That is, the waveguide mode layer 120 may be defined by the width (P) of each period unit, the width (W) of the waveguide element 121, and the height (H) of the waveguide element 121. there is. Here, each period unit may constitute a unit pixel. As illustrated in FIGS. 2 and 3 , for each period unit, the width P of the period unit and the width W and height H of the waveguide element 121 within the period unit may be defined. . The width W of the waveguide element 121 is smaller than the width P of the period unit, and accordingly, the opening 123 may be formed between adjacent period units in the first direction x. The width of each period unit in the second direction (y) may be the same as the width (P) in the first direction (x), but according to the embodiment, the width of each period unit in the second direction (y) It can be adjusted variously. In this case, the length of the waveguide element 121 in the second direction (y) may be formed equal to the width in the second direction (y) in units of periods.

The substrate 240 may support the absorption layer 110 , the waveguide mode layer 120 and the reflection layer 130 . To this end, the substrate 240 may be combined with the reflective layer 130 . More specifically, the reflective layer 130 , the absorbing layer 110 , and the waveguide mode layer 120 may be sequentially stacked on the substrate 240 . The substrate 240 may include a readout integrated circuit (ROIC) capable of detecting far infrared rays absorbed by the absorption layer 110 . The readout integrated circuit (ROIC) may detect the target based on the light absorption spectrum of far infrared rays.

According to an embodiment, the absorption layer 110 is disposed between the waveguide mode layer 120 and the reflection layer 130 and may be implemented as an nBn structure. More specifically, the absorption layer 110 includes a first n-contact layer 211, a second n-type electrode layer 213, an active layer 215, and a barrier layer 217. ) may be included.

The first n-type electrode layer 211 may be combined with the waveguide mode layer 120 . In other words, the waveguide mode layer 120 , that is, the waveguide element 121 may be disposed on the first n-type electrode layer 211 . For example, the thickness of the first n-type electrode layer 211 may be about 0.5 μm. A bias voltage may be applied to the first n-type electrode layer 211 and holes may be extracted.

The second n-type electrode layer 213 may be combined with the reflective layer 130 . In other words, the second n-type electrode layer 213 may be disposed on the reflective layer 130 . For example, the thickness of the second n-type electrode layer 213 may be about 0.1 μm. A bias voltage may be applied to the second n-type electrode layer 213 and electrons may be extracted.

The active layer 215 and the barrier layer 217 may be disposed between the first n-type electrode layer 211 and the second n-type electrode layer 213 . The active layer 215 may be combined with the first n-type electrode layer 211 . In other words, the active layer 215 may be disposed between the first n-type electrode layer 211 and the barrier layer 217 . For example, the active layer 215 may have a thickness of about 1.8 μm. The active layer 215 may serve to form a pair of electrons and holes by absorbing light.

The barrier layer 217 is for reducing dark current through electron blocking and may be combined with the second n-type electrode layer 213 . In other words, the barrier layer 217 may be disposed between the active layer 215 and the second n-type electrode layer 213 . For example, the barrier layer 217 may have a thickness of about 0.3 μm.

A current generated by absorbing far-infrared rays in the absorption layer 110 may be measured in a readout integrated circuit (ROIC) of the substrate 240 to detect the absorbed far-infrared rays.

Hereinafter, the performance of the photodetector 100 for the S-polarization component and the P-polarization component of far infrared rays will be described with reference to FIGS. 4 to 6 .

4 to 6 are graphs for explaining performance of a photodetector according to an embodiment of the present invention.

FIG. 4 shows absorptivity spectra for the S-polarized component and P-polarized component of far infrared rays of the photodetector 100 according to an embodiment of the present invention, and FIG. 5 shows the area of the absorbance spectrum for the S-polarized component in FIG. 4 . (S) is shown, and FIG. 6 is a diagram for explaining the optimal width W of the waveguide element 121 for maximizing the absorption spectrum area S.

Referring to FIG. 4 , it can be seen that the photodetector 100 according to the embodiment of the present invention including the waveguide mode layer 120 can detect far-infrared rays of a more extended wavelength band. That is, as the waveguide mode layer 120 is disposed on the absorption layer 110, the absorption layer 110 may have a further improved absorptance (A) for far-infrared rays of an extended wavelength band. In this case, the absorption layer 110 may have a further improved absorption rate (A) for both the S-polarized component and the P-polarized component of the far infrared ray. Specifically, when the waveguide mode layer 120 is not included, the detectable far infrared rays are in a wavelength range of about 8 μm to 9 μm, whereas the far infrared rays detectable by the photodetector 100 including the waveguide mode layer 120 are It shows a wavelength band of about 8 μm to 10 μm. In addition, the photodetector 100 can detect far-infrared rays of a more extended wavelength band with a remarkably low signal to noise ratio (SNR), as shown in the curve shown in FIG. 4 . Accordingly, the photodetector 100 according to an embodiment of the present invention may have a more improved absorption efficiency for far infrared rays of a more extended wavelength band.

The absorptance spectral area (S) for far-infrared rays in the photodetector 100 may be calculated based on the absorptivity (A) for far-infrared rays as shown in Equation 1.

Here, S represents an absorptivity spectrum area, A represents an absorptivity, and λ may be defined as a wavelength band, that is, a wavelength band of λ ₁ to λ ₂ .

Since the absorption rate (A) is also improved as a more expanded wavelength band is detected by the photodetector 100, the absorption spectrum area (S) will also be expanded. As an example, the photodetector 100 will have an absorptivity spectral area S as illustrated in FIG. 5 for an S-polarized component.

Accordingly, the size of the waveguide mode layer 120 for maximizing the absorption spectral area S may be calculated through optimization simulation. That is, the width (P) in units of period, the width (W) of the waveguide element 121, and the height (H) of the waveguide element 121 when the absorptivity spectrum area (S) is maximum can be calculated. In this case, the width (W) of the waveguide element 121 may be expressed as a product of the width (P) in period units and the fill factor of each waveguide element 121 for each period unit. Accordingly, based on the width P in units of period and the filling factor of the waveguide element 121, the optimum width W of the waveguide element 121 may be detected as shown in FIG. 6 . That is, the width (W) of the waveguide element 121 may be determined such that the area (S) of the absorption spectrum is maximized with respect to the width (P) in units of period.

Hereinafter, a method of manufacturing the photodetector 100 according to an embodiment of the present invention will be described with reference to FIGS. 7 to 12 .

7 is a flowchart illustrating a method of manufacturing a photodetector according to an embodiment of the present invention. 8 to 12 are cross-sectional views illustrating a method of manufacturing a photodetector according to an embodiment of the present invention.

7 to 12, the absorption layer 110 is prepared (S710). In one embodiment, the absorption layer 110 may have an nBn structure. Specifically, as illustrated in FIG. 8 , the absorption layer 110 may be formed on a donor substrate 810 . A first n-type electrode layer 211 may be formed on the donor substrate 810 . For example, the thickness of the first n-type electrode layer 211 may be about 0.5 μm. Also, an active layer 215 may be formed on the first n-type electrode layer 211 . For example, the active layer 215 may have a thickness of about 1.8 μm. And, a barrier layer 217 may be formed on the active layer 215 . For example, the barrier layer 217 may have a thickness of about 0.3 μm. Also, a second n-type electrode layer 213 may be formed on the barrier layer 217 . For example, the thickness of the second n-type electrode layer 213 may be about 0.1 μm.

Next, the absorption layer 110 is bonded onto the reflective layer 130 (S720). Specifically, as illustrated in FIG. 9 , a first reflective layer 831 may be formed on the absorption layer 110 and a second reflective layer 833 may be formed on the substrate 240 . Here, the first reflective layer 831 and the second reflective layer 833 may be made of the same material. For example, the first reflective layer 831 and the second reflective layer 833 may be made of a high reflectance metal material. Meanwhile, the substrate 240 may include a readout integrated circuit (ROIC). Also, the first reflective layer 831 may be coupled to the second reflective layer 833 so that the absorption layer 110 is inverted. Through this, as illustrated in FIG. 10 , a reflective layer 130 in which the first reflective layer 831 and the second reflective layer 833 are combined is formed on the substrate 240, and the absorbing layer 110 is formed on the reflective layer 130 can be placed on top. Then, as illustrated in FIG. 11 , the donor substrate 810 may be removed from the absorber layer 110 . Through this, one surface of the absorption layer 110 may be exposed.

Next, the waveguide mode layer 120 is formed on the absorption layer 110 (S730). Specifically, as illustrated in FIG. 12 , a plurality of waveguide elements 121 may be formed on the absorption layer 110 . A plurality of waveguide elements 121 may be arranged in a periodic structure on one surface of the absorption layer 110, and an opening 123 may be provided between the plurality of waveguide elements 121. In this case, the waveguide mode layer 120 may be divided into a plurality of period units defined around each waveguide element 121 . The size of the waveguide mode layer 120 may be defined as a width (P) in units of period, a width (W) of the waveguide element 121, and a height (H) of the waveguide element 121. The size of the waveguide mode layer 120 may be determined such that an absorption rate for a wavelength of far-infrared rays to be detected through each of the waveguide elements 121 is maximized in each of a plurality of period units. The waveguide element 121 may be made of a material having a high refractive index, that is, a refractive index higher than the refractive index of the atmosphere and similar to the refractive index of the absorption layer 110 . Also, the waveguide element 121 may be made of a dielectric material. For example, the waveguide element 121 may be made of a silicon (Si) material, and the refractive index of the silicon material may be about 3.6.

Accordingly, the photodetector 100 according to the embodiment of the present invention can be manufactured. According to an embodiment of the present invention, during operation of the photodetector 100, the waveguided mode layer 120 provides waveguided mode resonance absorption for the absorption layer 110, and the reflection layer 130 provides a waveguided mode resonance absorption for the absorption layer 110. , can provide Fabry-Perot resonant absorption. Through this, the absorption layer 110 can absorb far infrared rays incident through the openings 123 between the waveguide elements 121, far infrared rays propagated from the waveguide elements 121, and far infrared rays reflected from the reflective layer 130. In this case, the absorption layer 110 may absorb far-infrared rays incident through the openings 123 and far-infrared rays propagating from the waveguide element 121 through waveguide mode resonance absorption. Also, the absorption layer 110 may absorb far-infrared rays reflected from the reflective layer 130 through Fabry-Perot resonance absorption. Accordingly, the absorption layer 110 may have improved absorption efficiency with the help of the waveguide mode layer 120 and the reflection layer 130 . For this reason, even if the thickness of the absorption layer 110 is thin, the absorption layer 110 can absorb a sufficient amount of far infrared rays.

Therefore, the photodetector 100 according to an embodiment of the present invention can detect far infrared rays of a more expanded wavelength band. Specifically, far-infrared rays detectable by the photodetector 100 may represent a wavelength band of 8 μm to 10 μm. In addition, the photodetector 100 can detect far-infrared rays of a more extended wavelength band with a remarkably low signal-to-noise ratio. Accordingly, the photodetector 100 may have a more improved absorption efficiency for far-infrared rays of an extended wavelength band.

Various embodiments of this document and terms used therein are not intended to limit the technology described in this document to a specific embodiment, and should be understood to include various modifications, equivalents, and/or substitutes of the embodiment. In connection with the description of the drawings, like reference numerals may be used for like elements. Singular expressions may include plural expressions unless the context clearly dictates otherwise. In this document, expressions such as "A or B", "at least one of A and/or B", "A, B or C" or "at least one of A, B and/or C" refer to all of the items listed together. Possible combinations may be included. Expressions such as "first", "second", "first" or "second" may modify the elements in any order or importance, and are used only to distinguish one element from another. The components are not limited. When a (e.g., first) element is referred to as being “(physically or functionally) connected” or “connected” to another (e.g., second) element, that element is referred to as the other element. It may be directly connected to the element or connected through another component (eg, a third component).

According to various embodiments, each of the components described above may include a single entity or a plurality of entities. According to various embodiments, one or more components or operations among the aforementioned corresponding components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components may be integrated into one component. In this case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by the corresponding component among the plurality of components prior to integration. According to various embodiments, the actions performed by a module, program, or other component are executed sequentially, in parallel, iteratively, or heuristically, or one or more of the actions are executed in a different order, omitted, or , or one or more other operations may be added.

The drawings and detailed description of the present invention referred to so far are only examples of the present invention, which are only used for the purpose of explaining the present invention, and are used to limit the scope of the present invention described in the meaning or claims. It is not. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

100: photodetector 110: absorption layer
120: waveguide mode layer 121: waveguide element
123: opening 130: reflective layer
211: first n-type electrode layer 213: second n-type electrode layer
215: active layer 217: barrier layer
240: substrate 810: donor substrate
831: first reflective layer 833: second reflective layer

Claims (18)

an absorption layer for absorbing far infrared rays;
a waveguide mode layer including a plurality of waveguide elements arranged in a periodic structure on one surface of the absorption layer to propagate incident far-infrared rays to the absorption layer; and
A photodetector for detecting far-infrared rays comprising a reflection layer disposed on the other surface of the absorption layer to reflect far-infrared rays incident from the absorption layer. According to claim 1,
The absorbing layer absorbs far infrared rays incident to openings between the plurality of waveguide elements, far infrared rays propagated from the plurality of waveguide elements, and far infrared rays reflected from the reflective layer. According to claim 1,
The plurality of waveguide elements are made of a material having a higher refractive index than the refractive index of the air. According to claim 3,
The plurality of waveguide elements are made of a silicon material and a photodetector for detecting far-infrared rays. According to claim 1,
The reflective layer is a photodetector for detecting far-infrared rays made of a metal material. According to claim 1,
The absorbent layer,
a first n-type electrode layer coupled to the waveguide mode layer;
a second n-type electrode layer disposed on the reflective layer;
an active layer disposed between the first n-type electrode layer and the second n-type electrode layer; and
A photodetector for detecting far-infrared rays comprising a barrier layer disposed between the active layer and the second n-type electrode layer. According to claim 1,
The photodetector for detecting far-infrared rays further comprises a substrate combined with the reflection layer to support the reflection layer, the absorption layer, and the waveguide mode layer. According to claim 7,
The substrate is a photodetector for detecting far-infrared rays including a readout integrated circuit for detecting absorbed far-infrared rays. According to claim 1,
The waveguide mode layer is divided into a plurality of period units defined around each of the plurality of waveguide elements,
The size of the waveguide mode layer is defined by the width of each of the plurality of period units, the width of each of the plurality of waveguide elements, and the height of each of the plurality of waveguide elements, and the absorption spectrum area for each of the plurality of period units is the maximum. A photodetector for detecting far-infrared rays in which the width of each waveguide element is determined so that preparing an absorption layer for absorbing far infrared rays;
bonding the absorption layer to a reflection layer for reflecting far infrared rays incident from the absorption layer; and
A method of manufacturing a photodetector for detecting far-infrared rays, comprising forming a waveguide mode layer including a plurality of waveguide elements arranged in a periodic structure on the absorption layer to propagate incident far-infrared rays to the absorption layer, on the absorption layer. . According to claim 10,
The absorbing layer absorbs far-infrared rays incident to the openings between the plurality of waveguide elements, far-infrared rays propagated from the plurality of waveguide elements, and far-infrared rays reflected from the reflection layer. According to claim 10,
The method of manufacturing a photodetector for detecting far infrared rays, wherein the plurality of waveguide elements are made of a material having a refractive index higher than that of air. According to claim 12,
The method of manufacturing a photodetector for detecting far-infrared rays, wherein the plurality of waveguide elements are made of a silicon material. According to claim 10,
The method of manufacturing a photodetector for detecting far-infrared rays, wherein the reflective layer is made of a metal material. According to claim 10,
The step of combining the absorption layer on the reflection layer,
forming a first reflection layer on the absorption layer;
forming a second reflective layer on the substrate; and
and combining the first reflective layer with the second reflective layer to invert the absorption layer to form the reflective layer. According to claim 15,
Preparing the absorber layer,
Forming the absorber layer on a donor substrate;
The step of combining the absorption layer on the reflection layer,
The method of manufacturing a photodetector for detecting far-infrared rays, further comprising the step of removing the donor substrate from the absorption layer bonded to the reflection layer. According to claim 16,
Forming the absorption layer on the donor substrate,
forming a first n-type electrode layer on the donor substrate;
forming an active layer on the first n-type electrode layer;
forming a barrier layer on the active layer; and
A method of manufacturing a photodetector for detecting far-infrared rays, comprising forming a second n-type electrode layer on the barrier layer. According to claim 10,
The waveguide mode layer is divided into a plurality of period units defined around each of the plurality of waveguide elements,
The size of the waveguide mode layer is defined by the width of each of the plurality of period units, the width of each of the plurality of waveguide elements, and the height of each of the plurality of waveguide elements, and the absorption spectrum area for each of the plurality of period units is the maximum. A method of manufacturing a photodetector for detecting far-infrared rays, in which the width of each waveguide element is determined so that

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