CN114664968B - Visible-infrared dual-band photoelectric detector - Google Patents

Abstract

The visible-infrared dual-band photodetector provided in the embodiment of the present invention utilizes the PIN photoelectric detection structure and the metal-semiconductor contact interface barrier structure to improve the quantum efficiency of the mid- and far-infrared bands and at the same time realize the visible-infrared dual-band photodetector. Band detection function. The advantage is that when light is vertically incident, the visible light is fully absorbed and detected when passing through the PIN structure. Since silicon has good transmission performance for infrared band light, the infrared band light passes through the substrate layer and is reflected by the metal film reflective layer. The infrared band light is reflected to the microstructure layer, and the characteristics of the microstructure layer are used to enhance the absorption of infrared band light, causing the carriers to gain energy and jump to the Fermi level, crossing the potential barrier and entering the semiconductor substrate, causing electrons and holes to be absorbed respectively. The metal electrodes on both sides collect and absorb the infrared band light with high quantum conversion efficiency to achieve visible-infrared dual-band detection. This invention can greatly increase the detection spectrum range and broaden the application field.

Description

A visible-infrared dual-band photoelectric detector

Technical field

The invention relates to the field of photoelectric technology, and in particular to a visible-infrared dual-band photoelectric detector.

Background technique

As the main force of visible light and near-infrared band detection devices, silicon-based photodetectors have the advantages of high efficiency, low power consumption, small size, vibration resistance, low price and easy integration with circuits, and are widely used in various fields. Since the bandgap width of silicon is about 1.1eV, silicon responds in the visible and near-infrared bands. However, for photons with energy less than 1.1eV, due to the relatively large bandgap width of the silicon material, the silicon photodetector responds in the mid- and far-infrared bands. The light absorption is almost zero, which to a certain extent restricts the development of silicon-based photodetectors in the near-infrared and mid-far infrared light bands with wavelengths greater than 1.1 μm, and currently existing silicon-based photodetectors mainly perform single-band spectral detection , the detection spectrum range is limited and has limitations in wide-band detection, which limits its application in some fields.

Contents of the invention

Embodiments of the present invention provide a visible-infrared dual-band photodetector, which can absorb and detect infrared band light with high quantum conversion efficiency and simultaneously achieve visible-infrared dual-band detection. Compared with traditional detectors, the invention can greatly increase the detection spectrum range and expand the application field.

An embodiment of the present invention provides a visible-infrared dual-band photoelectric detector, which includes:

semiconductor substrate layer;

A metal reflective layer located on one side of the semiconductor substrate layer, and a reflective surface structure is provided on the side of the metal reflective layer that is in contact with the semiconductor substrate layer;

a first-type semiconductor layer located on the opposite side of the semiconductor substrate layer;

a microstructure layer and a second type semiconductor layer spaced apart from each other on the first type semiconductor layer;

a first anode located on the microstructure layer;

a third type semiconductor layer located on the second type semiconductor layer;

a first cathode located on the third type semiconductor layer, the first cathode having a hollow structure for light to pass;

a second cathode and a second anode located on the first type semiconductor layer and spaced apart from the first cathode and the first anode respectively, the first anode and the second cathode forming a set of electrodes, The second anode and the first cathode form another set of electrodes.

As an optional solution, the material of the semiconductor substrate layer is one of silicon, germanium, and SOI, the first-type semiconductor layer is a P-type semiconductor layer or an N-type semiconductor layer, and the second-type semiconductor layer The third type semiconductor layer is an I-type intrinsic semiconductor layer, and the third-type semiconductor layer is an N-type semiconductor layer or a P-type semiconductor layer.

As an optional solution, the material of the insulating layer is any one of polyimide, polymethylmethacrylate, epoxy resin or _SiO2 .

As an optional solution, the material of the first anode, the first cathode, the second anode and the second cathode is one or more alloys selected from gold, silver, copper, aluminum, chromium, nickel and titanium. .

As an optional solution, the doped ions of the P-type semiconductor layer are B ³⁺ , and the doped ions of the N-type semiconductor layer are P ⁵⁺ or As ⁵⁺ .

As an optional solution, the microstructure layer is directly plated with corresponding metals on silicon to form an alloy thin film, plating corresponding metals on porous silicon to form an alloy thin film, plating corresponding metals on grating-structured silicon to form an alloy thin film, or black phosphorus. The two-dimensional material composed of graphene and graphene is plated with one or more of the corresponding metals, the alloy film is PtSi or Pt ₂ Si, and the corresponding metal is Pt.

As an optional solution, the reflective surface structure is located at the geometric center of the metal reflective layer, and the reflective surface structure, the hollow structure, the second type semiconductor layer, and the third semiconductor layer are located at Vertical midlines are collinear.

As an optional solution, the cross-section of the visible-infrared dual-band photodetector is circular, square or hexagonal.

As an optional solution, the reflective surface structure is a cone.

As an optional solution, it includes: a stepped structure, the stepped structure includes a first boss located at the geometric center of the first type semiconductor layer and a first boss located at the geometric center of the first boss. A second boss, the first anode, the second anode and the microstructure layer are located on the first boss, and the first cathode and the second type semiconductor layer are located on the second boss. On the stage, an insulation layer is provided between the first anode and the second anode.

As an optional solution, it includes: a planar structure including a third boss located on the first-type semiconductor layer and surrounding the second-type semiconductor layer, the microstructure layer and The second anode is located on the third boss, and the first anode, the first cathode and the second anode are located on the same horizontal plane.

The visible-infrared dual-band photodetector provided in the embodiment of the present invention utilizes the PIN photoelectric detection structure and the metal-semiconductor contact interface barrier structure to improve the quantum efficiency of the mid- and far-infrared bands and at the same time realize the visible-infrared dual-band photodetector. Band detection function. The advantage is that when light is vertically incident, the visible light is fully absorbed and detected through the PIN structure. Since silicon has good transmission performance for infrared band light, the infrared band light passes through the substrate layer and is reflected by the metal film reflective layer, thereby converting the infrared band light into the infrared band. The light is reflected to the microstructure layer, and the characteristics of the microstructure layer are used to enhance the absorption of light in the infrared band, causing the carriers to gain energy and jump to the Fermi level, crossing the potential barrier and entering the semiconductor substrate, causing electrons and holes to be absorbed by both sides respectively. The metal electrode collects and absorbs the infrared band light with high quantum conversion efficiency to achieve visible-infrared dual-band detection. Compared with traditional detectors, the invention can greatly increase the detection spectrum range and broaden the application fields.

Description of the drawings

Figure 1 is a structural longitudinal cross-sectional view of a visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 2a is a circular top view of a visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 2b is a square-shaped top view of a visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 2c is a top view of a hexagonal shape of a visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 3 is a schematic diagram of the working optical path of a visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 4 is a longitudinal cross-sectional view of the structure of another visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 5 is a schematic diagram of the working optical path of another visible-infrared dual-band photodetector in an embodiment of the present invention;

Figure 6a is a top view of a circular shape of another visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 6b is a square-shaped top view of another visible-infrared dual-band photodetector provided in the embodiment of the present invention;

Figure 6c is a top view of a hexagonal shape of another visible-infrared dual-band photodetector provided in the embodiment of the present invention;

Figure 7a is a schematic structural diagram of a microstructure layer in a visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 7b is a schematic structural diagram of the microstructure layer in another visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 7c is a schematic structural diagram of the microstructure layer in yet another visible-infrared dual-band photodetector provided in an embodiment of the present invention;

Figure 7d is a schematic structural diagram of the microstructure layer in another visible-infrared dual-band photodetector provided in an embodiment of the present invention.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only These are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the scope of protection of the present invention.

The terms "first", "second", "third", "fourth", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe specific objects. Sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances so that the embodiments described herein can be practiced in sequences other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus that encompasses a series of steps or units and need not be limited to those explicitly listed. Those steps or elements may instead include other steps or elements not expressly listed or inherent to the process, method, product or apparatus.

As shown in Figure 1, an embodiment of the present invention provides a visible-infrared dual-band photodetector, which includes:

semiconductor substrate layer 6;

A metal reflective layer 7 located on one side of the semiconductor substrate layer 6, and a reflective surface structure is provided on the side of the metal reflective layer 7 that is in contact with the semiconductor substrate layer 6;

The first type semiconductor layer 5 located on the other side opposite to the semiconductor substrate layer 6;

The microstructure layer 4 and the second type semiconductor layer 3 are spaced apart from each other on the first type semiconductor layer 5;

a first anode 10 located on the microstructure layer 4;

a third-type semiconductor layer 2 located on the second-type semiconductor layer 3;

The first cathode 1 is located on the third type semiconductor layer 2. The first cathode 1 has a hollow structure for light to pass through. The hollow structure can be an annular opening for light to pass through;

A second cathode 9 and a second anode 8 are located on the first type semiconductor layer 5 and are spaced apart from the first cathode 1 and the first anode 10 respectively. The cathode 9 constitutes one set of electrodes, the second anode 8 and the first cathode 1 constitute another set of electrodes, and the two pairs of electrodes are not connected to each other.

It should be noted that the positional relationships mentioned in the embodiments of the present invention are based on the up, down, left, and right position relationships shown in the drawings for ease of understanding.

As an optional solution, the material of the semiconductor substrate layer 6 is one of silicon, germanium, and SOI (Silicon-On-Insulator, silicon on an insulating substrate), where SOI can realize an integrated circuit element. For dielectric isolation of the device, the first-type semiconductor layer 5 is a P-type semiconductor layer or an N-type semiconductor layer, the second-type semiconductor layer 3 is an I-type intrinsic layer, and the third-type semiconductor layer 2 corresponds to The N-type semiconductor layer or P-type semiconductor layer needs to ensure that the doping conditions are opposite, that is, the first-type semiconductor layer 5 is a P-type semiconductor layer, and the third-type semiconductor layer 2 corresponds to an N-type semiconductor layer, a P-type semiconductor layer and an N-type semiconductor layer. When the position of the semiconductor layer switches, the cathode and anode switch accordingly.

Through this application solution, the photoelectric conversion efficiency in the infrared spectrum can be enhanced while effectively solving the problem of visible-infrared dual-band detection. By using the PIN structure, visible light is vertically incident from the top layer to the detector absorption area, and is fully absorbed and detected after entering the P-type (or N-type) semiconductor layer or entering the I-type (intrinsic) semiconductor layer. At the same time, due to the infrared wavelength of silicon, The light has good transmission performance. The metal reflective layer is used to reflect the transmitted infrared spectrum light to the microstructure silicon layer, so that the infrared band light is fully absorbed and detected, allowing the light of each spectrum band to enter its own complete absorption zone, achieving dual Spectral detection greatly increases the detection spectrum range and broadens the application fields. At the same time, by rationally setting the structure and thickness of the microstructure layer, the absorption of mid- and far-infrared bands is enhanced and the photoelectric conversion efficiency is improved.

In this embodiment, the material of the insulating layer 11 can be any one of polyimide, polymethyl methacrylate, epoxy resin or SiO ₂ , and those of ordinary skill in the art can flexibly select according to needs. There is no restriction on this.

In this embodiment, the doped ions of the P-type semiconductor layer are B ³⁺ , and the doped ions of the N-type semiconductor layer are P ⁵⁺ or As ⁵⁺ . Those skilled in the art can flexibly choose according to needs. No restrictions.

In some embodiments, the materials of the first anode 10, the first cathode 1, the second anode 8 and the second cathode 9 are one or more of gold, silver, copper, aluminum, chromium, nickel, and titanium. alloy.

In some embodiments, the reflective surface structure is located at the geometric center of the metal reflective layer, and the reflective surface structure, the hollow structure, the second type semiconductor layer 3 and the third semiconductor layer 2 are located at The vertical center lines are collinear, and the reflective surface structure is a cone.

Furthermore, the structures of visible-infrared dual-band photodetectors can be divided into two types, namely stepped structure and planar structure, which are introduced separately below.

As shown in FIGS. 1 and 3 , in some embodiments, the stepped structure includes a first boss 51 located at the geometric center of the first type semiconductor layer 5 and a first boss 51 located at the geometric center of the first boss 51 . The second boss 52, the first anode 10, the second anode 8 and the microstructure layer 4 are located on the first boss 51, the first cathode 1, the second type semiconductor layer 3 is located on the second boss 52, and an insulating layer 11 is provided between the first anode 10 and the second anode 8. The insulating layer 11 is used to isolate the first anode 10 and the second anode 8 and prevent crosstalk. Specifically, According to the device structure, the stepped structure is arranged from top to bottom: first cathode 1, third type semiconductor layer 2, second type semiconductor layer 3, second anode 8, second cathode 9, first anode 10, insulation Layer 11, microstructure layer 4, first-type semiconductor layer 5, semiconductor substrate layer 6, and metal reflective layer 7.

As shown in Figure 2a, Figure 2b and Figure 2c, in some embodiments of the stepped structure, the cross-section of the visible-infrared dual-band photodetector is circular, square or hexagonal, and the electrodes include an anode and a cathode. , Correspondingly, the shape of the electrode can also be designed according to the overall shape. For example, when it is circular, the electrodes can be spaced around the center in a concentric circle. Similarly, when a square or hexagon is used, the electrodes can be concentrically spaced. The electrodes are arranged in a surrounding manner, and the shapes of the anode and cathode are one or a combination of outer ring, single strip, multiple strips, circle, inner ring, and inner polygon, which can be selected according to needs.

As shown in FIGS. 4 and 5 , in some embodiments, the planar structure includes a third boss 53 located on the first-type semiconductor layer 5 and surrounding the second-type semiconductor layer 3 . The microstructure The layer 4 and the second anode position 8 are on the third boss 53, and the first anode 10, the first cathode 1 and the second anode 8 are located on the same horizontal plane, specifically, a planar The structures from top to bottom are: first cathode 1, first anode 10, third type semiconductor layer 2, microstructure layer 4, second type semiconductor layer 3, first type semiconductor layer 5, second anode 8, third Two cathodes 9, semiconductor substrate layer 6, and metal reflective layer 7.

As shown in Figure 6a, Figure 6b and Figure 6c, in some embodiments of the planar structure, the cross-section of the visible-infrared dual-band photodetector is circular, square or hexagonal, and the electrodes include an anode and a cathode. , Correspondingly, the shape of the electrode can also be designed according to the overall shape. For example, when it is circular, the electrodes can be spaced around the center in a concentric circle. Similarly, when a square or hexagon is used, the electrodes can be concentrically spaced. The electrodes are arranged in a surrounding manner, and the shapes of the anode and cathode are one or a combination of outer ring, single strip, multiple strips, circle, inner ring, and inner polygon, which can be selected according to needs.

As shown in Figure 7a, Figure 7b, Figure 7c and Figure 7d, in some embodiments, the microstructure layer is formed by plating corresponding metals on silicon to form an alloy film, plating corresponding metals on porous silicon to form an alloy film, or a grating structure. Silicon is plated with a corresponding metal to form an alloy film, or a two-dimensional material composed of black phosphorus and graphene is plated with one or more of the corresponding metals. The alloy film is PtSi, Pt ₂ Si, etc., and the corresponding metal is Pt, etc., among which, 13 is a metal Pt film, 14 is a P-type (or N-type) silicon layer, 15 is a porous P-type (or N-type) silicon layer, 16 is a grating structure P-type (or N-type) silicon layer, 17 is a P-type (or N-type) black phosphorus layer (or graphene layer).

In order to improve the photoelectric conversion efficiency in the mid- and far-infrared bands, the design uses a microstructure layer, which usually includes porous structures, optical cavity structures, grating structures, two-dimensional materials and other structures, which are enhanced by increasing the specific surface area, using external field reflection, or using surface plasmons. The absorption of infrared light improves the photoelectric conversion efficiency to a certain extent and obtains the best quantum efficiency and frequency response.

The device of the present invention includes multiple metal electrodes and multiple doping layers. The device is mainly divided into two parts: the middle part mainly realizes high-performance detection of visible light bands, and the P-type (or N-type) semiconductors are sequentially from top to bottom. , I-type (intrinsic) semiconductor, N-type (or P-type) semiconductor; the parts on both sides mainly realize high-performance detection in the infrared band. From top to bottom, they are the microstructure layer, N-type (or P-type) semiconductor, and lining. Bottom layer and metal reflective layer.

The working principle of the visible-infrared dual-band detector provided in the embodiment of the present invention is introduced by taking the third-type semiconductor layer 2 as a P-type semiconductor layer and the second-type semiconductor layer 3 as an I-type semiconductor layer as an example:

As shown in Figure 3 and Figure 7, after the light enters the detector, the visible light part is absorbed in the third-type semiconductor layer 2 or after entering the second-type semiconductor layer 3; in the infrared band, the silicon in the semiconductor substrate layer 6 has With good transmission performance, the infrared band light passes through the semiconductor substrate layer 6 and is incident on the metal reflective layer 7 for reflection. The infrared band light is reflected to the microstructure layer 4 and absorbed. In the visible light absorption region (PIN structure): The light in the P region and I region is excited by light injection to generate electron-hole pairs. The electrons and holes quickly move toward the N region and P region under the action of the electric field, forming light Current; in the infrared absorption area: for the infrared band, a microstructured metal-semiconductor contact interface barrier structure is used, and the incident light is reflected to the microstructure layer 4 through the metal reflective layer 7. For N-type semiconductors, Schott is formed after the metal contacts the semiconductor. Based on the barrier structure, infrared photons pass through the semiconductor layer and are absorbed by the microstructure layer, causing the electrons to gain energy and jump to the Fermi level, leaving holes to cross the barrier and enter the semiconductor substrate. The electrons in the microstructure layer are collected, completing the infrared Detection; For P-type semiconductors, ohmic contact is formed after the metal contacts the semiconductor. Infrared photons pass through the semiconductor layer and are absorbed by the microstructure layer. There is only a small potential barrier for holes to enter the semiconductor from the metal. A relatively small voltage can make the holes Easily cross the potential barrier and enter the semiconductor to complete infrared detection. The electrons and holes are finally collected by the metal electrodes on both sides to achieve visible-infrared dual-band detection.

The visible-infrared dual-band photodetector provided in the embodiment of the present invention utilizes the PIN photoelectric detection structure and the metal-semiconductor contact interface barrier structure to improve the quantum efficiency of the mid- and far-infrared bands and at the same time realize the visible-infrared dual-band photodetector. Band detection function. The advantage is that when light is vertically incident, the visible light is fully absorbed and detected through the PIN structure. Since silicon has good transmission performance for infrared band light, the infrared band light passes through the substrate layer and is reflected by the metal film reflective layer, thereby converting the infrared band light into the infrared band. The light is reflected to the microstructure layer, and the characteristics of the microstructure layer are used to enhance the absorption of light in the infrared band, causing the carriers to gain energy and jump to the Fermi level, crossing the potential barrier and entering the semiconductor substrate, causing electrons and holes to be absorbed by both sides respectively. The metal electrode collects and absorbs the infrared band light with high quantum conversion efficiency to achieve visible-infrared dual-band detection. Compared with traditional detectors, the invention can greatly increase the detection spectrum range and broaden the application fields.

The above-mentioned specific embodiments do not constitute a limitation on the scope of the present invention. It will be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions are possible depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (9)

1. A visible-infrared dual-band photodetector, comprising:

a semiconductor substrate layer;

the metal reflecting layer is positioned on one side of the semiconductor substrate layer, and a reflecting surface structure is arranged on one side of the metal reflecting layer, which is attached to the semiconductor substrate layer;

a first type semiconductor layer located on the other surface opposite to the semiconductor substrate layer;

a microstructure layer and a second type semiconductor layer disposed on the first type semiconductor layer at intervals;

a first anode on the microstructured layer;

a third type semiconductor layer located on the second type semiconductor layer;

the first cathode is positioned on the third semiconductor layer and provided with a hollowed-out structure for light to pass through;

the second cathode and the second anode are arranged on the first semiconductor layer at intervals with the first cathode and the first anode respectively, the first anode and the second cathode form one group of electrodes, and the second anode and the first cathode form the other group of electrodes;

the semiconductor substrate layer is made of one of silicon, germanium and SOI, the first type semiconductor layer is a P type semiconductor layer or an N type semiconductor layer, the second type semiconductor layer is an I type intrinsic layer, and the third type semiconductor layer is an N type semiconductor layer or a P type semiconductor layer;

the microstructure layer is formed by directly plating corresponding metal on silicon to form an alloy film and black phosphorusPlating one or more of corresponding metals on the two-dimensional material and graphene, wherein the alloy film is PtSi or Pt ₂ Si, wherein the corresponding metal is Pt;

when detecting, visible light is absorbed and detected when passing through the PIN structure, infrared band light passes through the semiconductor substrate layer and is reflected by the metal reflecting layer, and the infrared band light is reflected to the microstructure layer.

2. The visible-infrared dual band photodetector of claim 1, wherein the material of said first anode, first cathode, second anode and second cathode is an alloy of one or more of gold, silver, copper, aluminum, chromium, nickel, titanium.

3. The dual-band visible-infrared photodetector of claim 1, wherein said P-type semiconductor layer is doped with ions B ³⁺ The doping ion of the N-type semiconductor layer is P ⁵⁺ Or As ⁵⁺ 。

4. The visible-infrared dual band photodetector of claim 1, wherein said reflective surface structure is located at a geometric center of said metal reflective layer, said reflective surface structure, said hollowed-out structure, said second type semiconductor layer, said third type semiconductor layer being collinear with a vertical centerline.

5. The visible-infrared dual band photodetector of claim 1, wherein the cross section of the visible-infrared dual band photodetector is circular, square or hexagonal.

6. The visible-infrared dual band photodetector of claim 4, wherein said reflective surface structure is a cone.

7. The visible-infrared dual band photodetector of claim 1, wherein said microstructured layer is an alloy film formed by plating a corresponding metal directly on porous silicon or an alloy film formed by plating a corresponding metal on silicon of a grating structure.

8. The visible-infrared dual band photodetector of any one of claims 1 to 7, comprising: the step-type structure comprises a first boss positioned at the geometric center of the first semiconductor layer and a second boss positioned at the geometric center of the first boss, the first anode, the second anode and the microstructure layer are positioned on the first boss, the first cathode and the second semiconductor layer are positioned on the second boss, and an insulating layer is arranged between the first anode and the second anode.

9. The visible-infrared dual band photodetector of any one of claims 1 to 7, comprising: the planar structure comprises a third boss which is arranged on the first type semiconductor layer and surrounds the second type semiconductor layer, the microstructure layer and the second anode are arranged on the third boss, and the first anode, the first cathode and the second anode are arranged on the same horizontal plane.