Photodetector, detection device, and fabricating method thereof

Abstract

A photodetector includes a semiconductor, a metal layer, a first electrode, and a second electrode. A composite structure array is made from a surface of semiconductor. The semiconductor forms a Schottky contact with at least a portion of the surface of the metal layer. The first electrode contacts with an upper surface of the metal layer, and the second electrode forms Ohmic contact with a lower surface of the semiconductor. Each composite structure includes a cavity to trap an incident light for inducing surface resonance and a center core structure within the cavity to gather electric field of resonance.

Description

Technical Field

[0001] This invention relates to a photodetector element, a detection device, and a method for manufacturing the same. Prior Technology

[0002] Currently, most infrared light detection devices use semiconductors with small band gaps, such as III-V group semiconductors or Ge, as the active layer or detection absorption material to detect infrared light with extremely low photon energy. Although the fabrication technology of existing III-V or Ge detectors is quite mature, these materials are relatively more expensive than other materials, and the fabrication process requires many complex and costly epitaxial devices. The detection principle of these devices is mostly semiconductor bandgap absorption (MBA), which involves carriers in the semiconductor being excited by incident light and crossing the semiconductor bandgap to generate a photocurrent. Therefore, to improve the device's detection efficiency or photoelectric response performance, these devices often require complex structural designs such as multiple quantum wells (MQWs) or multiple quantum dots (MQDs) in the active layer. For these reasons, the adoption rate of infrared light detection devices remains low.

[0003] The applicant's previous Republic of China patent application (publication number TWI686936B) discloses a photodetector with a metal / semiconductor junction that uses a different mechanism to detect infrared light and has advantages such as ease of fabrication and low cost. Fabricating an array of inverted or upright pyramid structures on the surface of the semiconductor enhances the surface plasma effect, confining incident light deep within the microstructure. The gradient linewidth of the pyramid structure allows all wavelengths of incident light to generate a larger response signal through this mechanism, resulting in good performance not only in the visible light range but also in the near-infrared range.

[0004] The applicant's previous Republic of China patent application (publication number TWI806274B) continued previous research by performing pre-processing and / or post-processing on the photodetector element, such as adding an insulating layer between the metal and the semiconductor to reduce noise and improve the signal-to-noise ratio (SNR). The resulting photodetector element has a response time of less than 10 microseconds.

[0005] The applicant's previous Republic of China patent application (application number 112127270) discloses a light absorption structure and a photodetector including the light absorption structure. The light absorption structure comprises an array of multiple inverted trapezoidal structures for absorbing incident light, particularly in the infrared band. The multiple inverted trapezoidal structures are made of a metal layer, and the cross-section of each inverted trapezoidal structure includes an upper base and a lower base, the length of the upper base being greater than the length of the lower base. Through the design of the trapezoidal structure, the response to a specific incident light band can be increased. Summary of the Invention

[0006] One aspect of the present invention provides a photodetector element comprising a semiconductor layer, a metal layer, a first electrode, and a second electrode. The semiconductor layer has a composite structure array composed of a plurality of composite structures. At least a portion of the surface of the metal layer forms a Schottky contact with the surface of the composite structure array, and the first electrode is in contact with the upper surface of the metal layer. The second electrode forms an ohmic contact with the lower surface of the semiconductor layer. Each composite structure includes a resonant cavity in which incident light resonates, and an intermediate core structure located within the resonant cavity for collecting and capturing resonant energy.

[0007] In some embodiments, the resonant cavity is shaped as an inverted pyramid, an inverted trapezoid, a cuboid, or a cup.

[0008] In some embodiments, the shape of the central core structure is an upright pyramid, a cylinder, a rectangular column, or a cone.

[0009] In some embodiments, the photodetector is used to detect incident light with a wavelength greater than 1.1 micrometers (μm).

[0010] In some embodiments, the responsivity of the photodetector is equal to or greater than 0.557 V / W for incident light at a wavelength of 3.46 μm.

[0011] In some embodiments, the first electrode is grid-shaped.

[0012] In some embodiments, the metal layers are conformally formed on the surface of the complex composite structure.

[0013] Another aspect of the present invention provides a method for manufacturing a photodetector, comprising: providing a semiconductor substrate; depositing a shielding layer on an upper surface and a lower surface of the semiconductor substrate respectively; depositing a photoresist layer on the upper surface of the semiconductor substrate above the shielding layer; exposing and developing the photoresist layer and the semiconductor substrate using a photomask as a shield to obtain a patterned photoresist layer; etching the shielding layer and the patterned photoresist layer to obtain a patterned shielding layer; etching the semiconductor substrate to form a composite structure array on the surface of the semiconductor substrate, wherein the composite structure array includes a plurality of composite structures, each composite structure including a resonant cavity for resonating incident light therein and an intermediate core structure located within the resonant cavity for collecting and capturing resonant energy; depositing a metal layer on the surface of the plurality of composite structures; depositing a first electrode on the metal layer; and depositing a second electrode on the lower surface of the semiconductor substrate.

[0014] In one embodiment, a metal layer system is conformally formed on the surface of the complex composite structure.

[0015] The photodetector element or array provided by this invention exhibits higher responsivity in the infrared band compared to previous studies, which is beneficial for applications in various real-time infrared light detection. Furthermore, the photodetector element and array have low manufacturing costs, can be mass-produced, and are easy to integrate with silicon-based processes. Simple Explanation of the Diagram

[0016] Figure 1 shows a photodetector element according to an embodiment of the present invention.

[0017] Figure 2A shows a WPS structure array formed on a semiconductor surface according to an embodiment of the present invention.

[0018] Figure 2B shows a method for fabricating a grid electrode according to an embodiment of the present invention.

[0019] Figure 3 shows the measurement architecture used in the experiments of this invention.

[0020] Figure 4 shows a simulation of the light field of the photodetector 1 shown in Figure 1.

[0021] Figure 5 shows top (1500x) and side (2500x) scanning electron microscope images of an example of a W-shaped composite pyramid structure array fabricated according to an embodiment of the present invention.

[0022] Figure 6 shows the incident light wavelength versus responsivity curves of a photodetector element with a W-type composite pyramid structure array (WPS) on a silicon surface with a period of 16 μm, and a photodetector element with an inverted pyramid structure array on a silicon surface with a period of 16 μm, fabricated according to an embodiment of the present invention.

[0023] Figures 7A, 7B, and 7C respectively show the light field simulation of the composite structure having only an inverted pyramid, a cubic column, and a cylindrical resonant cavity in some embodiments of the present invention.

[0024] Figure 8A shows a light field simulation of a composite structure comprising a cylindrical resonant cavity and a cylindrical intermediate core structure according to an embodiment of the present invention.

[0025] Figure 8B shows a light field simulation of a composite structure comprising a cubic resonant cavity and a cubic intermediate core structure according to an embodiment of the present invention.

[0026] Figure 8C shows a light field simulation of a composite structure comprising a cubic resonant cavity and a cubic intermediate core structure according to an embodiment of the present invention, wherein the height of the cubic intermediate core structure is greater than the height of the cubic resonant cavity.

[0027] Figure 9A shows a light field simulation of a composite structure with only an inverted trapezoidal shape according to an embodiment of the present invention.

[0028] Figure 9B shows a light field simulation of a composite structure with an inverted trapezoidal resonant cavity and a trapezoidal intermediate core structure according to an embodiment of the present invention.

[0029] Figure 10A shows a line graph of the incident light wavelength versus the integrated electric field for composite structures containing only cup-shaped, cube-shaped, trapezoidal, and inverted pyramid shapes.

[0030] Figure 10B shows a line graph of incident light wavelength versus integrated electric field for composite structures with cubic resonant cavity and cubic central core structure (CUB_CUB), inverted trapezoidal resonant cavity and trapezoidal central core structure (TRP_TRP), cylindrical resonant cavity and cylindrical central core structure (CIR_CIR), and inverted trapezoidal resonant cavity and upright pyramidal central core structure (TRP_PS).

[0031] Figure 10C shows a line graph of the incident light wavelength versus the integrated electric field for a composite structure containing only an inverted pyramid-shaped resonant cavity.

[0032] Figure 10D shows a line graph of the incident light wavelength versus the integrated electric field in the composite structure containing an inverted trapezoidal resonant cavity and an upright pyramidal central core structure.

[0033] Figures 11A and 11B are a perspective view and a cross-sectional view, respectively, showing an example of fabricating an inverted pyramid structure according to an embodiment of the present invention.

[0034] Figure 12 is a microscope photograph showing the light masks used in Figures 11A and 11B.

[0035] Figure 13 is a cross-sectional view showing an example of fabricating a composite structure according to an embodiment of the present invention.

[0036] Figure 14 is a microscope photograph showing the light mask used in Figure 13. Implementation

[0037] The various embodiments of this invention will be described in detail below, with illustrations provided. In addition to these detailed descriptions, the invention can be widely implemented in other embodiments, and any easy substitutions, modifications, or equivalent changes to these embodiments are included within the scope of this invention and are subject to the following patent claims. In the description of the specification, many specific details are provided to give the reader a more complete understanding of the invention; however, the invention may still be implemented even with some or all of these specific details omitted. Furthermore, well-known procedural steps or elements are not described in the details to avoid unnecessarily limiting the invention.

[0038] In various embodiments of Republic of China patent publications TWI686936B, TWI806274B, and application number 112127270, photodetectors with planar, inverted pyramid array, upright pyramid array, and inverted trapezoidal structure arrays on the semiconductor layer surface have been fabricated, exhibiting good current response results in the visible light band and near-infrared light. The entire contents of these patents are incorporated herein by reference and are considered part of the content of this case.

[0039] Figure 1 shows a photodetector 1 according to an embodiment of the present invention. Referring to Figure 1, the photodetector includes: a semiconductor layer 10, a metal layer 13, a first electrode 11, and a second electrode 12. A composite structure array is formed on the surface of the semiconductor layer 10 in a suitable manner, such as, but not limited to, dry etching and / or wet etching. Each composite structure includes a resonant cavity 102 that induces local surface plasma resonance (LSPR) therein with incident light, and an intermediate core structure 101 located within the resonant cavity 101 for collecting and capturing resonant energy.

[0040] In some embodiments, the shape of the resonant cavity 102 may be (but is not limited to): an inverted pyramid, an inverted trapezoid, a cuboid, or a cup.

[0041] In some embodiments, the shape of the central core structure 101 may be (but is not limited to): an upright pyramid, a cylinder, a vertical (elongated) column, or a cone.

[0042] Referring to Figure 1, for ease of explanation, in the illustrated embodiment, the resonant cavity 102 is trapezoidal in shape, and the central core structure 101 is an upright pyramid, forming a W-shaped composite pyramid structure. Each W-shaped composite pyramid structure has a cross-section containing an upper base and a lower base, with dimensions (lengths) L1 and L2 respectively, where L1 is greater than L2, and an upright pyramid is located in the central region of the lower base. Furthermore, the gradient linewidth W gradually increases from L2 to L1, corresponding to different wavelengths of incident light inducing local surface plasma resonance (LSPR) in the inverted trapezoidal structure. At least a portion of the surface of the metal layer 13 forms a Schottky contact with the surface of the W-shaped composite pyramid structure array. The first electrode 11 is in contact with the upper surface of the metal layer 13. The second electrode 12 forms an ohmic contact with the back surface of the semiconductor layer 10. Carriers in the metal layer 13 or semiconductor layer 10, excited by incident photons, form hot carriers that cross the interface between the metal and semiconductor layers, generating a photocurrent. It is not necessary to have a first electrode 11 above every two adjacent W-shaped composite pyramid structures; that is, the spacing between these interconnected electrodes can be larger. In the illustrated embodiment, the first electrode 11 is fence-shaped. In other embodiments, the first electrode 11 may also be finger-shaped or mesh-shaped.

[0043] Figures 11A and 11B are a perspective view and a cross-sectional view, respectively, showing an example of fabricating an inverted pyramid structure according to an embodiment of the present invention, wherein step (4) in Figure 11A corresponds to steps (4A) and (4B) in Figure 11B. In this example, the semiconductor is a silicon substrate and the metal layer is silver.

[0044] Referring to Figures 11A and 11B, step (1): Using a laser cutter, cut the silicon wafer into silicon substrates 50 with a size of 2.5 × 2.5 cm. Then, in sequence, place the silicon substrates 50 into an ultrasonic cleaner for 10 minutes each with IPA, acetone, IPA, and methanol to remove organic matter and dust from their surface.

[0045] Step (2): A 600 nm shielding layer 51, such as SiO2, is deposited on both sides of the silicon substrate 50 using a plasma-enhanced chemical vapor deposition (PECVD) system.

[0046] Step (3): Using a spin coater, spin coat HMDS onto the surface of the upper shielding layer 51 at an initial speed of 1000 rpm for 10 seconds and a final speed of 4000 rpm for 40 seconds; then spin coat a photoresist layer 52, such as ENPI-307 negative photoresist, onto the HMDS surface at a speed of 8000 rpm for 10 seconds. Then, soft bake the spin-coated silicon substrate 50 at a hot plate temperature of 110°C for 3 minutes.

[0047] Step (4A): Expose the sample to a rectangular photomask 53 as shown in Figure 12 for approximately 20 seconds, then bake at 130°C for 2 minutes. Step (4B): Next, develop the sample with MF-319 developer for approximately 40 seconds to obtain a patterned photoresist layer 54, which is a rectangular photoresist layer in this example; after confirming the rectangular pattern with an optical microscope (OM), bake the sample at 130°C for 3 minutes. In the microscope image of Figure 12, the yellowish areas contain metal (e.g., chromium), and if a positive photoresist is used, the darker areas contain metal.

[0048] Step (5): The patterned photoresist layer 54 and the upper shielding layer 51 are etched by reactive ion etching (RIE) to obtain the patterned shielding layer 55. When dry etching the shielding layer 51 (SiO2), the CHF3 flow rate is 30 sccm, the pressure is 1.30 Pa, the RF power is 90 W, and the time is 40 minutes. When etching the patterned photoresist layer 54, the O2 flow rate is 50 sccm, the pressure is 13.30 Pa, the RF power is 100 W, and the time is 10 minutes.

[0049] Step (6): The sample was wet-etched for 7 minutes with KOH at a concentration of 45wt% to produce a silicon substrate with an inverted pyramid structure 56 (IPS) on the surface.

[0050] Step (7) BOE: In a cleanroom, immerse the silicon substrate 50 in BOE etching solution for about 10 minutes to remove residual SiO2 on the upper and lower surfaces. Finally, clean the sample with deionized water and dry it with a nitrogen gun.

[0051] Figure 13 is a cross-sectional view showing the fabrication process of a W-type composite pyramid structure according to an embodiment of the present invention, wherein the semiconductor is an n-type silicon substrate and the metal layer is silver.

[0052] Referring to Figure 13, step (1): Using a laser cutter, cut the silicon wafer into silicon substrates 50 with a size of 2.5×2.5 cm. Then, in sequence, place the silicon substrates 50 into an ultrasonic cleaner for 10 minutes each with IPA, acetone, IPA, and methanol to remove organic matter and dust from their surface.

[0053] Step (2): Use a plasma-enhanced chemical vapor deposition (PECVD) system to deposit a 600 nm shielding layer, such as SiO2, on both sides of the silicon substrate.

[0054] Step (3): Using a spin coater, spin coat HMDS onto the surface of the upper masking layer at an initial speed of 1000 rpm for 10 seconds and a final speed of 4000 rpm for 40 seconds; then spin coat a photoresist layer, such as ENPI-307 negative photoresist, onto the HMDS surface at a speed of 8000 rpm for 10 seconds. Next, soft-bake the spin-coated silicon substrate at a hot plate temperature of 110°C for 50 minutes.

[0055] Step (4): Expose the sample to the 57 shaped photomask shown in Figure 14 for approximately 33 seconds, then bake at 130°C for 2 minutes. In the microscope image of Figure 14, the yellowish areas represent the light-blocking material, such as metal (e.g., chromium). If a positive photoresist is used, the darker areas will also have a light-blocking material (e.g., metal). The photomask has an array of light-blocking patterns, each containing a light-transmitting core portion, or each light-blocking pattern having an outer pattern and a core pattern within that outer pattern. In this example, if a negative photoresist is used, the square outer pattern contains a light-transmitting square core portion; if a positive photoresist is used, both the outer and core patterns are square. When fabricating other composite structures, the outer pattern and core portion or core pattern can be other shapes, such as circles, polygons, etc.

[0056] Step (5): Next, develop the sample with MF-319 developer for about 55 seconds to obtain a patterned photoresist layer 54. In this example, it is a zigzag photoresist layer. After confirming the zigzag pattern with an optical microscope (OM), bake it at 130°C for 3 minutes.

[0057] Step (6): The patterned photoresist layer 54 and the upper shielding layer 51 are etched by reactive ion etching (RIE) to obtain the patterned shielding layer 55. When dry etching the shielding layer 51 (SiO2), the CHF3 flow rate is 30 sccm, the pressure is 1.30 Pa, the RF power is 90 W, and the time is 45 minutes. When etching the patterned photoresist layer 54, the O2 flow rate is 50 sccm, the pressure is 13.30 Pa, the RF power is 100 W, and the time is 15 minutes.

[0058] Step (7): The sample was wet-etched with a KOH solution with a concentration of 45wt% to produce a silicon substrate with a composite pyramid structure 58 (WPS) on the surface.

[0059] Step (8): In a cleanroom, immerse the silicon substrate in BOE etching solution to remove the SiO2 on the surface, then clean the silicon substrate with deionized water, and finally dry it with a nitrogen gun.

[0060] Following the structure in step (8) of Figure 13, the metal layer (active layer), the first electrode, and the second electrode (back electrode) are then fabricated by vapor deposition:

[0061] For example, a 100 nm thick layer of aluminum is deposited on the bottom surface of a silicon substrate as a back electrode at a deposition rate of 1 Å / s. A 10 nm thick active layer is deposited on the surface of a WPS structure array at a deposition rate of 0.1 Å / s.

[0062] Next, a 200nm thick Ag gate electrode is fabricated: as shown in step (1) of Figure 2B, a finger electrode mask is placed on top of the component, and 10nm is deposited at a deposition rate of 0.1 Å / s, 10nm at 0.3 Å / s, 10nm at 0.5 Å / s, and finally 70nm at 1 Å / s to form a gate electrode on one side. As shown in step (2) of Figure 2B, the gate electrode is then rotated 180° and deposited again at 0.1 Å / s, 10nm at 0.3 Å / s, 10nm at 0.5 Å / s, and finally 70nm at 1 Å / s, for a total thickness of 200nm, thus completing the gate electrode.

[0063] Figure 3 shows the measurement architecture used in the experiments of this invention. Referring to Figure 3, the measurement architecture includes a light source 30, a chopper 31, a device under test (DUT) 32, a multifunction power meter 33 (Keithley 2400), a computer 34, a controller 37, a lock-in amplifier 38, and a reflector 39. The DUT 32 is, for example, the photodetector 1 shown in Figure 1. When measuring the VT diagram, the light source 30 is a ceramic heating element that is heated to 300˚C to generate blackbody radiation. The slow chopper 40 is connected to the controller 41 (Arduino, model Leonardo). Through the controller 41, the slow chopper 40 can be fixed to have fixed on and off times, for example, 5~15 seconds on and 5~15 seconds off, allowing the light path 36 to pass through or not, to generate an ON-OFF period of 10~30 seconds. Controller 37 connects to fast chopper 31 and lock-in amplifier 38. Controller 37 turns fast chopper 31 on / off at a predetermined (fast) frequency. Lock-in amplifier 38 captures the signal according to this predetermined frequency and filters out other noise. If needed, such as when measuring VT, a reflective tube 39 may be placed between fast chopper 31 and light source 30. If needed, a bandpass filter 35 may be placed between device under test 32 and light source 30. The distance between device under test 32 and light source 30 can be 10 cm. The electrical signal generated by device under test 32 after receiving light can first pass through lock-in amplifier 38, then be received by multi-function power meter 33 (Keithley 2400), and finally transmitted to computer 34 for processing. The measurement architecture is usually covered by a box to prevent light leakage.

[0064] Figure 4 shows the optical field simulation of the photodetector 1 shown in Figure 1. The fabricated W-shaped composite pyramid structure combines the structures of an inverted pyramid and an upright pyramid, with the upright pyramid bulging at the center of the bottom helping to concentrate the electric field and enhance the resonance effect. The optical field simulation shows that the W-shaped composite pyramid structure can effectively enhance the electric field resonance.

[0065] Figure 5 shows top-view (1500x) and side-view (2500x) scanning electron microscope (SEM) images of the fabricated W-shaped composite pyramid array. The top-view and side-view SEM images reveal that the W-shaped composite pyramid array exhibits a periodic, upright pyramid structure with a central convex protrusion.

[0066] Figure 6 shows the incident light wavelength versus responsivity curves for the photodetector with a W-type composite pyramid structure array (WPS) on a silicon surface with a period of 16 μm and an inverted pyramid structure array on a silicon surface. As shown in Figure 6, compared to the inverted pyramid structure array, the device with the W-type composite pyramid structure array on a silicon surface exhibits a significantly improved responsivity in the infrared band. For example, at a wavelength of 3.46 μm, the responsivity of the WPS device is approximately 4.72 times higher than that of the IPS device.

[0067] Figures 7A, 7B, and 7C respectively show the light field simulation of the composite structure having only an inverted pyramid, a cubic column, and a cylindrical resonant cavity in some embodiments of the present invention.

[0068] Figure 8A shows a light field simulation of a composite structure comprising a cylindrical resonant cavity and a cylindrical intermediate core structure according to an embodiment of the present invention.

[0069] Figure 8B shows a light field simulation of a composite structure comprising a cubic resonant cavity and a cubic intermediate core structure according to an embodiment of the present invention.

[0070] Figure 8C shows a light field simulation of a composite structure comprising a cubic resonant cavity and a cubic intermediate core structure according to an embodiment of the present invention, wherein the height of the cubic intermediate core structure is greater than the height of the cubic resonant cavity.

[0071] Figure 9A shows a light field simulation of a composite structure with only an inverted trapezoidal shape according to an embodiment of the present invention.

[0072] Figure 9B shows a light field simulation of a composite structure with an inverted trapezoidal resonant cavity and a trapezoidal intermediate core structure according to an embodiment of the present invention.

[0073] Figure 10A shows a line graph of the incident light wavelength versus the integrated electric field for composite structures containing only cup-shaped, cube-shaped, trapezoidal, and inverted pyramid shapes.

[0074] Figure 10B shows line graphs of incident light wavelength versus integrated electric field for the composite structures with cubic resonant cavity and cubic central core structure (CUB_CUB), inverted trapezoidal resonant cavity and trapezoidal central core structure (TRP_TRP), cylindrical resonant cavity and cylindrical central core structure (CIR_CIR), and inverted trapezoidal resonant cavity and upright pyramidal central core structure (TRP_PS). As shown in Figure 10B, the (CUB_CUB) composite structure has the strongest resonant electric field for incident light with wavelengths of approximately 5.5 μm to 6 μm, the (TRP_TRP) composite structure has the strongest resonant electric field for incident light with wavelengths of approximately 4 μm, and the (CIR_CIR) composite structure has the strongest resonant electric field for incident light with wavelengths of approximately 4.5 μm to 5 μm.

[0075] Figure 10C shows a line graph of the incident light wavelength versus the integrated electric field for a composite structure containing only an inverted pyramid resonant cavity.

[0076] Figure 10D shows a line graph of the incident light wavelength versus integrated electric field for the composite structure containing an inverted trapezoidal resonant cavity and an upright pyramidal central core structure (TRP_PS). As shown in Figure 10D, the (TRP_PS) composite structure exhibits the strongest resonant electric field for incident light wavelengths of approximately 2 μm and 3 μm to 4 μm. These results demonstrate that photodetector elements with different composite structures can be fabricated for the desired wavelength bands.

[0077] The photodetector elements in the above embodiments use specific materials, but other materials, such as those described in TW Patent Publication Nos. TWI686936B and TWI806274B, may also be used in other embodiments. For example, the metal layer may comprise gold, silver, copper, chromium, nickel, or combinations thereof. In some embodiments, a detection device with an array of photodetector elements is provided, wherein the array of photodetector elements is composed of one or more photodetector elements described herein. The construction of the detection device can be referenced to the applicant's Republic of China Patent Application No. 114107022, filed on February 26, 2023. The entire contents of the above patent are incorporated herein by reference and are considered a part of this specification. In some embodiments, the detection device is a thermal imaging device.

[0078] In some embodiments, the detection device is used to detect one or more test gases. The detection device further includes a gas chamber in which the one or more test gases are disposed. After the light source passes through the one or more test gases, it is received by the photodetector array and converted into an electrical signal.

[0079] In one embodiment, the light source is a light source with wavelengths covering near-infrared (NIR) to mid-wave infrared (MWIR), and the detection device further includes one or more reflective / lenses and a filter array. The light source passes through the one or more reflective / lenses disposed in the air chamber, and then through the filter array, before being received by the light detection element array and converted into an electrical signal.

[0080] In one embodiment, the light source is a light source with wavelengths covering near-infrared (NIR) to mid-wave infrared (MWIR), and the detection device further includes a beam splitter. After the light source passes through the beam splitter disposed in the air chamber, it is received by the light detection element array and converted into an electrical signal.

[0081] In one embodiment, the light source includes a plurality of narrowband light sources to emit monochromatic beams of different wavelengths, which, after passing through one or more gases to be measured, are received by the photodetector array and converted into electrical signals.

[0082] In one embodiment, the gas chamber includes a plurality of gas channels that are interconnected but do not interfere with each other in terms of optical path. Each gas channel contains one or more gases to be measured. After the monochromatic light beams pass through one of the gas channels, they are received by one or more corresponding photodetectors in the photodetector array and converted into electrical signals.

[0083] Unless otherwise stated, all figures or expressions used in the specification (except for the claims) such as those indicating dimensions, physical properties, etc., are to be understood as being modified by the term "approximately" in all cases. At a minimum, each numerical parameter described in the specification or claims that is modified by the term "approximately" should be interpreted in accordance with the figures mentioned and the application of rounding techniques.

[0084] The above embodiments of the present invention are merely for illustrating the technical ideas and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the patent scope of the present invention. All other equivalent changes or modifications made without departing from the spirit disclosed in the present invention are covered within the scope disclosed in the present invention and should be included in the patent application scope below.

[0085] 1: Photodetector 10: Semiconductor layer 11: First electrode 12: Second electrode 13: Metal layer 30: Light source 31: Fast Chopper 32: Component under test 33: Multifunctional power meter 34: Computer 35: Passband filter 36: Optical Path 37: Controller 38: Lock-in amplifier 39: Reflector tube 40: Slow Chopper 41: Controller 50: Silicon substrate 51: Shielding layer 52: Photoresist layer 53: Square-shaped light mask 54: Patterned photoresist layer 55: Patterned masking layer 56: Inverted pyramid structure 57: Rectangular light mask 58: Composite Pyramid Structure 101: Intermediate Core Structure 102: Resonance cavity L1: Size L2: Size W: Width

Claims

1. A photodetector element, comprising: a semiconductor layer having a composite structure array composed of a plurality of structures; a metal layer having at least a portion of its surface forming a Schottky contact with the surface of the composite structure array; a first electrode in contact with the upper surface of the metal layer; and a second electrode in an ohmic contact with the lower surface of the semiconductor layer; wherein, Each of these composite structures includes a resonant cavity in which an incident light resonates, and an intermediate core structure located within the resonant cavity for collecting and capturing resonant energy.

2. The photodetector element of claim 1, wherein the resonant cavity is shaped as an inverted pyramid, an inverted trapezoid, a cuboid, or a cup.

3. The photodetector element of request item 1 or 2, wherein the shape of the intermediate core structure is an upright pyramid, cylinder, rectangular prism, trapezoid, or cone.

4. The photodetector element of claim 1, wherein the photodetector element is used to detect the incident light with a wavelength greater than 1.1 micrometers (μm).

5. The photodetector element of claim 1, wherein the responsivity of the photodetector element for incident light of wavelength 3.46 μm is equal to or greater than 0.557 V / W.

6. The photodetector element of claim 1, wherein the first electrode is grid-shaped.

7. The photodetector element of claim 1, wherein the first electrode is mesh-like.

8. The photodetector element of claim 1, wherein the metal layer system is conformally deposited on the surface of the plurality of composite structures.

9. The photodetector element of claim 1, wherein the thickness of the metal layer is approximately 10 nm.

10. A method for manufacturing a photodetector, comprising: providing a semiconductor substrate; depositing a shielding layer on an upper surface of the semiconductor substrate; depositing a photoresist layer on the upper surface of the semiconductor substrate above the shielding layer; exposing and developing the semiconductor substrate and the photoresist layer using a photomask as a mask to obtain a patterned photoresist layer, the photomask comprising an array of light-shielding patterns, each light-shielding pattern in the array comprising a light-transmitting core portion, or each light-shielding pattern comprising a peripheral pattern and a core pattern located within the peripheral pattern; etching the shielding layer and the patterned photoresist layer to obtain a patterned shielding layer; etching the semiconductor substrate to form a composite structure array on the surface of the semiconductor substrate, wherein the composite structure array comprises a plurality of composite structures, each composite structure comprising a resonant cavity for resonating an incident light therein and an intermediate core structure located within the resonant cavity for collecting and capturing resonant energy; and depositing a metal layer on the surface of the plurality of composite structures. A first electrode is deposited on the metal layer; and a second electrode is deposited on the lower surface of the semiconductor substrate.

11. The method for manufacturing the light-detecting element as claimed in claim 10, wherein the light-shielding pattern is a square shape.

12. The method of manufacturing the photodetector element of claim 10, wherein a metal layer system is conformally formed on the surface of the plurality of composite structures.

13. A detection device for detecting a light source, the detection device comprising an array of photodetectors, the array of photodetectors comprising one or more photodetectors as described in any one of claims 1 to 9.

14. The detection device as claimed in claim 13, wherein the detection device is a thermal imaging device.

15. The detection device of claim 13, wherein the detection device is used to detect one or more test gases, the detection device further includes a gas chamber in which the one or more test gases are disposed, and the light source passes through the one or more test gases and is received by the photodetector array and converted into an electrical signal.

16. The detection device of claim 15, wherein the light source is a light source with wavelengths covering near-infrared (NIR) to mid-wave infrared (MWIR), the detection device further comprising one or more reflective / lenses and a filter array, wherein the light source passes through the one or more reflective / lenses disposed in the air chamber, and then through the filter array, and is received by the light detection element array and converted into an electrical signal.

17. The detection device of claim 15, wherein the light source is a light source with wavelengths covering near-infrared (NIR) to mid-wave infrared (MWIR), and the detection device further includes a beam splitter, wherein the light source, after passing through the beam splitter disposed in the air chamber, is received by the light detection element array and converted into an electrical signal.

18. The detection apparatus of claim 15, wherein the light source comprises a plurality of narrowband light sources to emit monochromatic light beams of different wavelengths, the monochromatic light beams passing through the one or more gases to be measured and then received by the photodetector array and converted into electrical signals.

19. The detection device of claim 18, wherein the gas chamber comprises a plurality of gas channels interconnected but whose optical paths do not interfere with each other, each gas channel accommodating one or more gases to be measured, and the monochromatic light beams passing through one of the gas channels are received and converted into electrical signals by one or more corresponding photodetectors in the photodetector array.

Images