KR20160135540A - Light detecting device - Google Patents

Abstract

A light detecting device is disclosed. A light detecting device comprises a first nitride layer; an electrostatic discharge (ESD) prevention layer which is located on the first nitride layer and includes an undoped nitride based semiconductor; a light absorption layer which is positioned on the ESD prevention layer; a Schottky junction layer which is located on the light absorption layer; and a first electrode and a second electrode which are electrically connected to the Schottky junction layer and the first nitride layer, respectively. The average n-type dopant doping concentration of the ESD protection layer is lower than the average n-type dopant doping concentration of the first nitride layer. So, high light detection efficiency can be achieved.

Description

[0001] LIGHT DETECTION DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor photodetector, and more particularly, to a semiconductor photodetector having high detection efficiency for light of a specific wavelength and improved electrostatic discharge characteristics.

A semiconductor photodetector element is a semiconductor element that operates using the principle that current flows when light is applied. Particularly, a semiconductor photodetecting device for detecting ultraviolet light can be applied in various fields such as commercial, medical, military, and telecommunication, so that the importance is high. In a photodetector using a semiconductor, a depletion region is generated by the separation of electrons and holes in the semiconductor by the irradiated light, and a current flows in accordance with the flow of electrons generated thereby.

Conventionally, a semiconductor photodetector element manufactured using silicon has been used. However, the semiconductor photodetecting device manufactured using silicon requires a high applied voltage for driving and has a disadvantage of low detection efficiency. Particularly, when a semiconductor photodetecting element for detecting ultraviolet light is manufactured using silicon, the photodetecting efficiency is deteriorated due to the characteristics of silicon having high sensitivity not only for ultraviolet light but also for visible light and infrared light. Further, the ultraviolet light detecting element using silicon is unstable thermally and chemically.

Thus, a photodetecting device using a nitride-based semiconductor has been proposed. The photodetecting device using nitride-based semiconductor has higher reactivity and response rate, lower noise level, and higher thermal and chemical stability than silicon photodetecting devices. Among the nitride-based semiconductors, in particular, a photodetecting device using AlGaN as a light absorbing layer shows excellent characteristics as an ultraviolet light detecting device.

Such a nitride-based semiconductor photodetecting device is manufactured with various structures, and is manufactured with a structure such as a photoconductor, a Schottky junction photodetector, or a photodetector in the form of p-i-n.

In the case of a p-i-n optical device, the light to be detected must pass through the p-type semiconductor layer, but the light loss due to the p-type semiconductor layer is considerably deteriorated. On the other hand, in the case of a Schottky junction photodetecting device, light passes through a thin Ni layer and is incident on the light absorption layer, and since the Ni layer also functions as a current spreading layer, it has excellent in-device characteristic uniformity and excellent light extraction efficiency.

The Schottky junction light detecting element generally includes a substrate, a buffer layer located on the substrate, a light absorbing layer located on the buffer layer, and a Schottky junction layer located on the light absorbing layer. Further, the first electrode and the second electrode are respectively formed on the Schottky junction layer, the buffer layer, or the light absorption layer. In order for the Schottky junction optical detecting element to be used as an ultraviolet light detecting element, the light absorbing layer is formed of a nitride semiconductor having band gap energy capable of absorbing ultraviolet light. Accordingly, AlGaN is mainly used as a semiconductor material constituting the light absorbing layer. On the other hand, a GaN layer is generally used as the buffer layer.

In addition, the GaN layer, the InGaN layer and the AlGaN layer used as the light absorbing layer in the conventional gallium nitride semiconductor photodetecting device fundamentally have defects. Due to such defects, a current flows in the device in response to visible light not ultraviolet light do. The response characteristic of such a semiconductor photodetector is measured to have a UV-to-Visible rejection ratio as low as about 10 ³ . That is, since the conventional semiconductor photodetector element reacts not only with ultraviolet light but also with visible light, a low current flows, and the detection accuracy is low.

Furthermore, the Schottky junction photodetecting device has the advantage of being relatively simple in structure, easy to manufacture, and high in efficiency. However, since the bandgap difference between the Schottky junction layer and the light absorption layer is small and the Schottky barrier is not sufficiently high The depletion region is not thick enough and is very susceptible to electrostatic discharge. Therefore, defective devices can easily occur due to the electrostatic discharge, so that the reliability is lowered, and there is a problem that the optical detection accuracy is reduced according to continuous use.

A problem to be solved by the present invention is to provide a photodetecting device having high light detection efficiency with respect to light of a wavelength to be detected, specifically ultraviolet light.

A further object of the present invention is to provide a method for producing a photodetecting device having a light absorbing layer excellent in crystallinity and having a high light detection efficiency for ultraviolet light.

Another object to be solved by the present invention is to provide a photodetector having excellent electrostatic discharge characteristics and excellent reliability.

A photodetecting device according to an aspect of the present invention includes: a first nitride layer; An ESD (Electrostatic Discharge) prevention layer located on the first nitride layer and including an undoped nitride based semiconductor; A light absorption layer disposed on the ESD prevention layer; A Schottky junction layer located on the light absorption layer; And a first electrode and a second electrode electrically connected to the Schottky junction layer and the first nitride layer, respectively, wherein the average n-type dopant doping concentration of the ESD protection layer is greater than the average n-type dopant doping of the first nitride layer Concentration.

The ESD protection layer may include at least one undoped nitride based semiconductor layer, and the undoped nitride based semiconductor layer may have a total thickness of 300 nm to 400 nm.

The photodetecting device may further include a low current blocking layer located between the ESD prevention layer and the light absorption layer and including a multi-layer structure layer.

Each interlayer interface of the multi-layer structure layer may have a band gap larger than that of each layer.

The ESD protection layer may include a doped region including an n-type dopant.

The doped region may include a first doped region, a second doped region located on the first doped region, and a third doped region located on the second doped region, wherein the doped region of the second doped region The concentration may be higher than the doping concentration of the first doping region and the doping concentration of the third doping region may be higher than the doping concentration of the second doping region.

The first doped region may be in contact with the second doped region, and the second doped region may be in contact with the third doped region.

In at least one of the first to third doped regions, the n-type dopant concentration may increase, decrease, or have a modulation doped profile along the direction toward the light absorbing layer side.

The doped region may include at least one n-type dopant shock region.

The undoped nitride-based semiconductor may be located on the upper and lower portions of the doped region.

The undoped nitride based semiconductor of the ESD prevention layer may contact at least one of the low current blocking layer and the first nitride layer.

The light absorption layer may include at least one of AlGaN and AlInGaN.

The multilayer structure layer of the low current blocking layer may include a superlattice structure in which an AlxGa (1-x) N layer and an AlyGa (1-y) N layer (x? Y) are repeatedly laminated.

The low current blocking layer may have a higher defect density than the light absorbing layer.

The photodetecting device may further include a substrate located under the first nitride layer, the first electrode is located on the Schottky junction layer, the second electrode is located on the first nitride layer And can be electrically contacted.

And the light absorption layer is flip-bonded to the secondary substrate so as to face the bottom surface of the photodetector.

The light absorbing layer may be disposed to face the bottom surface of the photodetecting device, the first electrode may be located below the Schottky junction layer, and the second electrode may be located above the first nitride layer.

The band gap energy of the first nitride layer may be greater than the band gap energy of the light absorption layer.

The band gap energy of the first nitride layer may be greater than the band gap energy of the light absorption layer.

According to the present invention, it is possible to provide a photodetecting device including a low current blocking layer and having low reactivity to visible light. Accordingly, the photodetecting device can have a visible light response rate as compared to a high ultraviolet ray, and can have high light detection efficiency and reliability.

In addition, according to the method for manufacturing a photodetector of the present invention, it is possible to provide a photodetecting device which can improve the crystallinity of a light absorbing layer and prevent microcurrent generated in response to visible light.

Furthermore, the photodetecting device of the present invention can be provided with an electrostatic discharge (ESD) prevention layer, so that the photodetecting device with improved electrostatic discharge characteristics can be provided. In particular, a photodetecting device having a Schottky junction type and excellent in characteristics for electrostatic discharge can be provided.

1 and 2 are a cross-sectional view and a plan view for explaining a light detecting element according to an embodiment of the present invention.
FIGS. 3 to 8 are cross-sectional views illustrating a method of manufacturing a photodetector according to another embodiment of the present invention.
9 is a graph for explaining the characteristics of the photodetector according to an experimental example of the present invention.
10 is a cross-sectional view for explaining a light detecting element according to another embodiment of the present invention.
11 is a cross-sectional view for explaining a light detecting element according to another embodiment of the present invention.
12 is an enlarged view and a graph for explaining an ESD prevention layer structure of a photodetecting device according to another embodiment of the present invention.
13 is an enlarged view and a graph for explaining an ESD prevention layer structure of a photodetecting device according to another embodiment of the present invention.
14 is a graph for comparing characteristics of the photodetector according to another experimental example of the present invention.
15 is a sectional view for explaining a light detecting element according to another embodiment of the present invention.
16 is a cross-sectional view for explaining a light detecting element according to another embodiment of the present invention.
17 and 18 are cross-sectional views for explaining a photodetecting device and a growth substrate separation method according to embodiments of the present invention.
19 is a TEM (transmission electron microscope) photograph and a graph for explaining the low current blocking layer of the photodetector according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can sufficiently convey the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. It is also to be understood that when an element is referred to as being "above" or "above" another element, But also includes the case where there are other components in between. Like reference numerals designate like elements throughout the specification.

The respective composition ratios, growth methods, growth conditions, thicknesses, etc. for the semiconductor layers described below are examples, and the following description does not limit the present invention. For example, in the case of being denoted by AlGaN, the composition ratio of Al and Ga can be variously applied according to the needs of ordinary artisans. In addition, the semiconductor layers described below can be grown using a variety of methods commonly known to those of ordinary skill in the art (such as MOCVD (Metal Organic Chemical Vapor Deposition), MBE (Molecular Beam Epitaxy), or HVPE (Hydride Vapor Phase Epitaxy). However, in the embodiments described below, the semiconductor layers are described as being grown in the same chamber using MOCVD, and the source gases introduced into the chamber may use source gases known to those skilled in the art depending on the composition ratio. The invention is not limited thereto.

1 and 2 are a cross-sectional view and a plan view for explaining a light detecting element according to an embodiment of the present invention.

1 and 2, the photodetecting device includes a first nitride layer 130, a low current blocking layer 140, a light absorbing layer 150, and a Schottky bonding layer 160. Furthermore, the photodetecting device may further include a substrate 110, a second nitride layer 120, a first electrode 171, and a second electrode 173.

The substrate 110 is located at the bottom of the device and is not limited as long as it can grow semiconductor layers. For example, the substrate 110 may include a nitride-based substrate such as a sapphire substrate, a SiC substrate, a ZnO substrate, a GaN substrate, or an AlN substrate. In this embodiment, the substrate 110 may be a sapphire substrate. The substrate 110 may be omitted.

The first nitride layer 130 may be located on the substrate 110. The first nitride layer 130 may include a nitride based semiconductor layer, for example, a GaN layer. The first nitride layer 130 may further include an impurity such as Si to be doped n-type or undoped. Since the nitride-based semiconductor can have n-type characteristics even in the undoped state, it is possible to determine whether doping is necessary or not. When the first nitride layer 130 is doped with n-type impurities including Si, the doping concentration of the Si may be 1 x 10 ⁸ or less. On the other hand, the first nitride layer 130 may have a thickness of about 2 탆.

Meanwhile, a second nitride layer 120 may be further disposed between the first nitride layer 130 and the substrate 110. The second nitride layer 120 may include a material similar to the first nitride layer 130 and may include, for example, a GaN layer. The second nitride layer 120 may have a thickness of about 25 nm and may have grown at a relatively low temperature (e.g., 500-600 占 폚) relative to the first nitride layer 130. [ The second nitride layer 120 may serve to improve the crystallinity of the first nitride layer 130 so that the second nitride layer 120 may be further formed, Optical and electrical properties can be improved. In addition, when the substrate 110 is a heterogeneous substrate such as a sapphire substrate, the second nitride layer 120 may serve as a seed layer on which the first nitride layer 130 can be grown.

Also, each of the first and second nitride layers 130 and 120 may be a single layer or multiple layers. The first nitride layer 130 may comprise GaN layers grown at different process conditions and may include layers grown at different growth temperatures, growth pressures and source flow conditions, for example. Accordingly, the concentration of the n-type dopant in the first nitride layer 130 may vary depending on the growth direction. Further, when the first nitride layer 130 includes a three-component system such as AlGaN or InGaN or a four-component system nitride semiconductor such as AlInGaN, nitride semiconductor layers having different composition ratios may be formed. For example, the first nitride layer 130 may include at least one u-GaN layer and at least one n-GaN layer formed on the u-GaN layer. Further, the at least one u-GaN layer and at least one n-GaN layer may be respectively formed in plurality, and the plurality of u-GaN layers and the plurality of n-GaN layers may be formed of u- GaN layers and n-GaN layers. The low current blocking layer 140 is located on the first nitride layer 130 and may include a multi-layered layer.

The multi-layered structure layer may include a two-element to four-element nitride semiconductor layer containing (Al, In, Ga) N, and further, the multi-layered structure layer may include at least two or more nitride layers having different composition ratios, Gt; structure. ≪ / RTI > At this time, each nitride layer may have a thickness of 5 to 10 nm. The multi-layered structure layer may include a structure in which 3 to 10 pairs of nitride layers having a pair of different composition ratios are stacked.

The nitride semiconductor layers stacked on the multi-layer structure layer may be determined according to the composition of the nitride layer of the light absorption layer 150. For example, when the light absorbing layer 150 includes an AlGaN layer, the multi-layered structure layer may include an AlN layer / AlGaN layer or an AlGaN layer / AlGaN layer. When the light absorption layer 150 includes InGaN, the multi-layered structure layer may include a repeated stacked structure of an InGaN layer / InGaN layer, a GaN layer / InGaN layer, or an AlInGaN layer / AlInGaN layer, ) May include a GaN layer / InGaN layer, an InGaN layer / InGaN layer, or a GaN layer / GaN repeating layer structure in the case of including the GaN layer.

Meanwhile, the low-current blocking layer 140 may have a multi-layer structure layer, and the band gap energy of the interface of each layer may be larger than that of a relatively different portion. 19 (a) and 19 (b) are data and TEM photographs measured using an atom probe to measure the respective composition ratios. The light absorbing layer has a depth of 0 to 90 nm and a low current blocking layer 140 at a depth greater than 90 nm, that is, at the lower end of the light absorbing layer. As shown in Figs. 19 (a) and 19 (b), it can be seen that the Al composition ratio is high between the respective layers of the multilayer structure layer. When a thin layer having a high Al composition ratio is present at the interface of the layers of the multi-layer structure layer, the interface resistance generated between the light absorption layer 150 and the first nitride layer 130 through the tunneling effect of generated photoelectrons is more effectively lowered The loss of photoelectrons is reduced and the sensitivity of the measurement is increased.

The lamination structure of the nitride layers having different composition ratios can be provided by growing the respective nitride layers at different pressures. For _{example, Al x Ga (1-x} ) N layer and the _{Al y Ga (1-y)} N if the layer is formed in a multilayer structure layer including a repeated stacked _{structure, Al x Ga (1-x} ) N Layer is grown at a pressure of about 100 Torr, and the Al _y Ga _(1-y) N layer is grown at a pressure of about 400 Torr. In this case, the Al _x Ga _(1-x) N layer grown at lower pressure has a higher Al composition ratio than the Al _y Ga _(1-y) N layer grown at higher pressure, Lt; / RTI >

Thus, the nitride layers grown at different pressures can have different growth rates due to differences in growth pressures. By having the different growth rates of the nitride layers, it is possible to prevent the dislocations from propagating in the growth process or to change the propagation path of the dislocations, thereby reducing the dislocation density of other semiconductor layers grown in the subsequent process. Further, when the composition ratio of the layers repeatedly stacked is different from each other, the stress due to the difference in lattice constant can be relaxed, so that the crystallinity of the other semiconductor layers grown in the subsequent process can be improved, Can be prevented. In particular, when an AlGaN layer having an Al ratio of 15% or more is grown on the low-current blocking layer 140, cracks can be effectively prevented from occurring in the AlGaN layer, and an AlGaN layer is conventionally formed on the AlN layer or the GaN layer It is possible to solve the problem of cracking in forming. According to the present embodiment, the low current blocking layer 140 including the multi-layer structure layer is formed under the light absorbing layer 150 to improve the crystallinity of the light absorbing layer 150, Can be prevented. When the light absorbing layer 150 has excellent crystals, the quantum efficiency of the light detecting element can be improved.

On the other hand, the low current blocking layer 140 may have a higher defect density than the light absorbing layer 150. The low current blocking function of the current blocking layer 140 will be described later in detail.

Referring again to FIG. 1, the light absorption layer 150 is located on the low current blocking layer 140.

The light absorption layer 150 may include a nitride semiconductor, and may include at least one of a GaN layer, an InGaN layer, an AlInGaN layer, and an AlGaN layer, for example. Since the size of the energy band gap is determined depending on the kind of the Group III element contained in the nitride semiconductor layer, the nitride semiconductor material of the light absorbing layer 150 can be determined in consideration of the wavelength of light to be detected in the light detecting element. For example, the photodetecting element for detecting ultraviolet light in the UVA region may include a light absorbing layer 150 having a GaN layer or an InGaN layer, and the photodetecting element for detecting ultraviolet light in the UVB region may contain not more than 28% And a light absorbing layer 150 including an AlGaN layer having an Al composition ratio, and the photodetecting device for detecting ultraviolet light in the UVC region may include a light absorbing layer (for example, an AlGaN layer having an Al composition ratio of 28% to 50% 150). However, the present invention is not limited thereto.

The light absorption layer 150 may have a thickness of about 0.1 to 0.5 占 퐉 and may have a thickness of 0.1 占 퐉 or more for the purpose of improving light detection efficiency. In the conventional case, since the light absorbing layer 150 is formed on the AlN layer or the GaN layer, if the light absorbing layer 150 including the AlGaN layer having the Al composition ratio of 15% is formed to a thickness of 0.1 탆 or more, . Therefore, the thickness of the light absorbing layer 150 is thinner than 0.1 占 퐉 in the related art, resulting in low device production yield and light detection efficiency. On the other hand, since the light absorption layer 150 is formed on the low-current blocking layer 140 including the multi-layered structure, cracks are prevented from being generated in the light absorption layer 150, (150). Therefore, the photodetecting device of the present invention has high light detection efficiency.

The Schottky junction layer 160 is located on the light absorption layer 150. The Schottky junction layer 160 and the light absorption layer 150 may form a Schottky contact with each other and the Schottky junction layer 160 may be formed of ITO, Ni, Co, Pt, W, Ti, Pd, Ru, Cr , And Au. The thickness of the Schottky junction layer 160 may be adjusted in consideration of light transmittance and Schottky characteristics, and may be formed to a thickness of 10 nm or less, for example.

Furthermore, the photodetecting device may further include a cap layer (not shown) positioned between the Schottky junction layer 160 and the light absorption layer 150. The cap layer may be a p-type doped nitride semiconductor layer including an impurity such as Mg. The cap layer may have a thickness of 100 nm or less, and preferably 5 nm or less. The cap layer can improve the Schottky characteristic of the device.

Referring again to FIG. 1, the photodetecting device may include a region where the light absorption layer 150 and the low-current blocking layer 140 are partially removed so that the surface of the first nitride layer 130 is exposed. The second electrode 173 may be disposed on the exposed region of the first nitride layer 130 and the first electrode 171 may be disposed on the Schottky junction layer 160.

The first electrode 171 may include a metal and may be formed of multiple layers. For example, the first electrode 171 may include a Ni layer / Au layer. The second electrode 173 may form an ohmic contact with the first nitride layer 130 and may be formed of multiple layers including a metal. For example, the second electrode 173 may include a structure in which a Cr layer / a Ni layer / an Au layer are stacked. However, the present invention is not limited to the above-mentioned examples. That is, the first electrode 171 and the second electrode 173 are not limited as long as they are electrically connected to the Schottky junction layer 160 and the first nitride layer 130, respectively.

Hereinafter, the role of the low-current blocking layer 140 according to the driving principle of the photodetector will be described in detail.

An external power source is connected to the first electrode 171 and the second electrode 173 of the photodetecting device so that the photodetecting device is prepared in a state where no voltage is applied or a reverse voltage is applied. When the prepared light detecting element is irradiated with light, the light absorbing layer 150 absorbs the light irradiated to the light detecting element. When the Schottky coupling layer 160 is formed on the light absorption layer 150, an electron-hole separation region, that is, a depletion region is formed between the interfaces. A current is generated by electrons formed by the irradiated light, and the function of photo detection can be performed by measuring the generated current.

For example, when the light detecting element is an ultraviolet light detecting element, an ideal ultraviolet light detecting element has an infinite value of UV-to-visible rejection ratio with respect to ultraviolet light. However, in the conventional ultraviolet light detecting element, due to defects of the light absorbing layer, the light absorbing layer also reacts with visible light to generate a current. Therefore, in the conventional photodetecting device, the visible light response ratio to ultraviolet light is measured to be 10 ³ or less, which causes an error in optical measurement.

On the other hand, in the case of the photodetecting device of the present invention, electrons generated in the light absorption layer 150 by visible light are captured by the low current blocking layer 140, so that driving of the device by visible light can be minimized. As described above, the low current blocking layer 140 has a higher defect density than the light absorbing layer 150. [ The electrons generated by the visible light are much smaller than the electrons generated by the ultraviolet rays, and therefore, the defects existing in the low-current blocking layer 140 can sufficiently prevent electron migration. That is, the low current blocking layer 140 has a defect density higher than that of the light absorbing layer 150, thereby preventing migration of electrons generated by visible light. On the other hand, since the number of electrons generated by irradiation of ultraviolet light to the light absorption layer 150 is much greater than the number of electrons generated by visible light, the current is not captured by the low current blocking layer 140 . Therefore, the photodetecting device of the present invention has a very low degree of reactivity with visible light, and can have a visible light response ratio higher than that of a conventional ultraviolet light detecting device with respect to ultraviolet light. In particular, the photodetecting device of the present invention has a visible light response ratio to ultraviolet rays of 10 ⁴ or more. Therefore, according to the present invention, a photodetecting device having high detection efficiency and reliability can be provided.

FIGS. 3 to 8 are cross-sectional views illustrating a method of manufacturing a photodetector according to another embodiment of the present invention. In the present embodiment, the same components as those described with reference to Figs. 1 and 2 will not be described in detail.

Referring to FIG. 3, a second nitride layer 120 may be formed on a substrate 110.

The second nitride layer 120 may comprise a nitride semiconductor and may be grown using MOCVD. For example, a Ga source and an N source may be implanted into a chamber at a temperature of about 550 DEG C and a pressure of 100 Torr. Accordingly, the second nitride layer 120 may comprise a low-temperature grown GaN layer. The second nitride layer 120 may be grown to a thickness of about 25 nm and the second nitride layer 120 may be grown to a thin thickness at a low temperature so that the first nitride layer 120 is crystalline, And excellent electrical characteristics can be obtained.

Next, referring to FIG. 4, a first nitride layer 130 is formed on the second nitride layer 120 using MOCVD.

The first nitride layer 130 may comprise a nitride semiconductor and may be grown using MOCVD. For example, a Ga source and an N source may be implanted into a chamber at a temperature between about 1050 DEG C and 1300 DEG C and a pressure between about 100 Torr and 500 Torr, whereby the first nitride layer 130 is grown at a high temperature Gt; GaN < / RTI > Also, the first nitride layer 130 may include an n-doped GaN layer by further implanting an Si source upon growth, or alternatively may include an undoped GaN layer. The first nitride layer 130 may be grown to a thickness of about 2 [mu] m to 3 [mu] m. In addition, the first nitride layer 130 may include a plurality of layers, in this case, a plurality of u-GaN and / or n-GaN layers grown at different process conditions.

Referring to FIG. 5, a low-current blocking layer 140 is formed on the first nitride layer 130.

The current blocking layer 140 may include a multi-layered structure layer, and the multi-layered structure layer may be formed by repetitively laminating a two to four-element nitride layer containing (Al, In, Ga) N. The multi-layered structure layer may be at least two or more nitride layers having different composition ratios. The nitride layers deposited on the multi-layer structure layer may be determined according to the composition of the nitride layer of the light absorption layer 150. For example, when the light absorbing layer 150 includes an AlGaN layer, the multi-layered structure layer may include an AlN layer / AlGaN layer or an AlGaN layer / AlGaN layer. When the light absorption layer 150 includes InGaN, the multi-layered structure layer may include a repeated stacked structure of an InGaN layer / InGaN layer, a GaN layer / InGaN layer, or an AlInGaN layer / AlInGaN layer, ) May include a GaN layer / InGaN layer, an InGaN layer / InGaN layer, or a GaN layer / GaN repeating layer structure in the case of including the GaN layer. The repeating layer structures may be formed by stacking 3 to 10 pairs of layers, and the thickness of the low current blocking layer may be 10 to 100 nm.

Each of the at least two nitride layers having different composition ratios may be grown to a thickness of 5 to 10 nm and the source gas may be grown to have different composition ratios by controlling the inflow amount. Alternatively, at least two or more nitride layers having different composition ratios may be formed by laminating the nitride layers at different pressures in the chamber while maintaining other conditions including the source gas flow rate constant.

For _{example, Al x Ga (1-x} ) N layer and the _{Al y Ga (1-y)} N if the layer is formed in a multilayer structure layer including a repeated stacked _{structure, Al x Ga (1-x} ) N Layer is grown at a pressure of about 100 Torr, and the Al _y Ga _(1-y) N layer is grown at a pressure of about 400 Torr. In this case, the Al _x Ga _(1-x) N layer grown at lower pressure has a higher Al composition ratio than the Al _y Ga _(1-y) N layer grown at higher pressure, Lt; / RTI > The low current blocking layer 140 including the multi-layer structure formed by growing at different pressures prevents the generation and propagation of dislocations in the growth process, so that the light absorbing layer 140 formed on the low current blocking layer 140 150) can be improved. In addition, nitride layers grown at different pressures and having different composition ratios are repeatedly laminated, so that stress due to the difference in lattice constant can be relaxed, and cracks can be prevented from being generated in the light absorption layer 150. Further, since the nitride layer is grown by changing only the pressure while the inflow amount of the source gas is kept constant, the step of forming the low current blocking layer 140 is easy.

On the other hand, the low current blocking layer 140 may have a higher defect density than the light absorbing layer 150. The current blocking layer 140 has a defect density relatively higher than that of the light absorbing layer 150 so that the light absorbing layer 150 can prevent electrons generated due to the reaction with visible light.

Referring to FIG. 6, a light absorption layer 150 is formed on the low-current blocking layer 140.

The light absorption layer 150 may include a nitride semiconductor, and may be grown by selectively applying an element and a composition of the nitride semiconductor according to the wavelength of light to be detected in the light detecting device. For example, when a photodetecting device for detecting ultraviolet light in a UVA region is manufactured, a light absorbing layer 150 having a GaN layer or an InGaN layer can be grown, and a photodetector element for detecting ultraviolet light in a UVB region It is possible to grow the light absorbing layer 150 including the AlGaN layer having an Al composition ratio of 28% or less in the case of manufacturing the photodetecting device, and when the photodetecting device for detecting ultraviolet light in the UVC region is manufactured, the Al composition ratio The light absorption layer 150 including the AlGaN layer having the AlGaN layer can be grown. However, the present invention is not limited thereto.

The light absorbing layer 150 can be grown to have a thickness of 0.1 mu m or more, and thus the produced photodetecting device can have high light detection efficiency.

Referring to FIG. 7, the first nitride layer 130 may be partially exposed by partially removing the light absorption layer 150 and the low-current blocking layer 140. Further, a portion of the first nitride layer 130 under the exposed portion may be further removed in the thickness direction.

Partial removal of the light absorption layer 150 and the low current blocking layer 140 may be performed through a photolithography and etching process, for example, dry etching may be used.

Next, referring to FIG. 8, a Schottky barrier layer 160 is formed on the light absorption layer 150. The Schottky barrier layer 160 may be formed by a deposition process or the like using a material including at least one of ITO, Ni, Co, Pt, W, Ti, Pd, Ru, Cr and Au. The thickness of the Schottky junction layer 160 may be adjusted in consideration of light transmittance and Schottky characteristics, and may be formed to a thickness of 10 nm or less, for example.

Further, the manufacturing method may further include forming a cap layer (not shown) positioned between the Schottky barrier layer 160 and the light absorption layer 150. The cap layer can be formed by growing a p-type doped nitride semiconductor layer containing an impurity such as Mg. The cap layer may have a thickness of 100 nm or less, and preferably 5 nm or less. The cap layer can improve the Schottky characteristic of the device.

Subsequently, when the first electrode 171 and the second electrode 173 are formed on the regions where the Schottky junction layer 160 and the first nitride layer 130 are exposed, Device is provided.

The first and second electrodes 171 and 173 may be formed using a deposition and lift-off process of a metal material, or may be formed of multiple layers. For example, the first electrode 171 may be formed by laminating a Ni layer / Au layer, and the second electrode 173 may be formed by laminating a Cr layer / a Ni layer / an Au layer.

Experimental Example 1

9 is a graph for explaining the characteristics of the photodetecting device according to an example of the present invention, and is a graph showing the wavelength versus reactivity of the photodetecting device. The light detecting elements used in Fig. 9 include the configurations of the present invention. The UVA photodetecting device uses a GaN layer as a light absorbing layer, and the UVB light detecting device uses an AlGaN layer having an Al composition ratio of 28% as a light absorbing layer, and the UVC light detecting device has an Al composition ratio of 50% AlGaN layer is used.

Each of the light detecting elements has a high reactivity as shown in Fig. In addition, each photodetecting device was measured for the response obtained by irradiating a white LED having a peak wavelength of 600 nm, and the ratio of visible light to ultraviolet light was calculated to be 10 ⁴ or more for all three photodetecting devices.

10 is a cross-sectional view for explaining a light detecting element according to another embodiment of the present invention. The photodetecting device of FIG. 10 differs from the photodetecting device of FIG. 1 in that it further includes an electrostatic discharge (ESD) prevention layer 180. Hereinafter, the photodetecting device of this embodiment will be described in more detail with the focus on the difference, and detailed description of the same configuration will be omitted.

The photodetecting device includes a first nitride layer 130, a light absorbing layer 150, a Schottky bonding layer 160, and an ESD prevention layer 180. Furthermore, the photodetecting device may further include a substrate 110, a second nitride layer 120, a low current blocking layer 140, a first electrode 171, and a second electrode 173.

The ESD protection layer 180 is located between the first nitride layer 130 and the low current blocking layer 140. The ESD prevention layer 180 may include a nitride-based semiconductor such as (Al, In, Ga) N, and may include, for example, GaN. In addition, the average n-type dopant concentration of the ESD protection layer 180 may be lower than the average n-type dopant concentration of the first nitride layer 130. Further, the ESD prevention layer 180 may include an undoped nitride-based semiconductor, for example, may include u-GaN, or may be formed of u-GaN. The ESD protection layer 180 may be grown and formed under process conditions that are generally similar to the first nitride layer 130. Further, the thickness of the ESD prevention layer 180 may be smaller than the thickness of the low-current blocking layer 140. For example, the ESD protection layer 180 may include at least one undoped nitride based semiconductor layer, and the total thickness of the undoped nitride based semiconductor layers may be about 200 nm to 400 nm, further, about 300 nm to 400 nm Lt; / RTI > However, the present invention is not limited thereto.

The ESD protection layer 180 has a relatively low average n-type dopant concentration and further includes an undoped nitride-based semiconductor, thereby improving the electrostatic discharge characteristics of the photodetecting device. In particular, the ESD prevention layer 180 including the undoped nitride semiconductor is located between the first nitride layer 130 and the light absorption layer 150, so that the internal capacitance of the photodetector can be improved, Increases resistance to discharge. Thus, the photodetecting device of the present embodiment has a Schottky junction structure, and can have resistance to electrostatic discharge several times or more as compared with the conventional one.

On the other hand, the photodetecting device of this embodiment may include nitride-based semiconductors having various composition ratios depending on the wavelength of light to be detected. For example, the light detecting element may be an element for detecting ultraviolet light in the UVB band. At this time, the light absorption layer 150 may include at least one of AlGaN and AlInGaN, and may be made of AlGaN having an Al composition ratio of about 30% or less, for example. Further, the low-current blocking layer 140 may include a superlattice structure in which an Al _x Ga _(1-x) N layer and an Al _y Ga _(1-y) N layer . However, the present invention is not limited thereto.

12 and 13 are enlarged views and graphs for explaining the ESD prevention layer structure of the photodetecting device according to another embodiment of the present invention, respectively; and FIG. 11 is a cross-sectional view for explaining a photodetector according to another embodiment of the present invention. Respectively. 12 and 13 each show an enlarged view of the ESD protection layer 190 and FIG. 13 (b) shows the change of the n-type dopant concentration along the direction toward the light absorption layer 150 side.

11 differs from the photodetecting device of FIG. 10 in that the ESD prevention layer 190 further includes a doped region. Hereinafter, the photodetecting device of this embodiment will be described in more detail with the focus on the difference, and detailed description of the same configuration will be omitted.

The photodetecting device includes a first nitride layer 130, a low current blocking layer 140, a light absorbing layer 150, a Schottky bonding layer 160, and an ESD prevention layer 190. Furthermore, the photodetecting device may further include a substrate 110, a second nitride layer 120, a first electrode 171, and a second electrode 173. The ESD protection layer 190 is substantially similar to the ESD protection layer 180 of FIG. 10, but may further include a doped region including an n-type dopant. The n-type dopant may include a known dopant such as Si, Ge, Sn or the like.

13, an ESD protection layer 190 according to one embodiment may include at least one of the doped regions 192, 193, and 194. The doped regions 192, 193 and 194 may include a first doped region 192, a second doped region 193 and a third doped region 192 194). The second doped region 193 may be located on the first doped region 192 and the third doped region 194 may be located on the second doped region 193. At this time, the respective doped regions 192, 193, and 194 may be in contact with each other or may be spaced apart from each other.

Also, the doped regions 192, 193, and 194 may have different doping concentrations. Further, the doping profile of the doped regions 192, 193, 194 may increase or decrease along a particular direction. For example, as shown in FIG. 13 (b), the second doped region 193 may have a higher doping concentration than the first doped region 192, and the third doped region 194 may have a doping concentration higher than that of the second doped region 192 193). ≪ / RTI > Accordingly, the doping concentration of the first to third doped regions 192, 193, and 194 may increase along the direction toward the light absorption layer 150 side. At this time, the rate of increase of the doping concentration may be constant or irregular. In addition, the doping profile within the one doped region 192, 193, or 194 may increase or decrease, and the n-type dopant may also have a modulation-doped doping profile. In the present embodiment, the first nitride layer 130 includes n-type dopant. However, the present invention is not limited thereto. The first nitride layer 130 may be in an undoped state. In addition, the average doping concentration in the first nitride layer 130 and the average doping concentration of the ESD prevention layer 190 can be variously adjusted.

The photoelectrons generated in the light absorption layer 150 pass through the third doped region 194 and horizontally move through the first doped region 192 to be transferred to the second electrode 173. At this time, the third doped region 194 is made to have a high concentration so that the photoelectrons can easily enter the electron dispersion layer and horizontally move through the first doped region 192. When the doping concentration is high, the degree of diffusion is increased, so that the first doped region 192 of the upper layer is allowed to be optically transparent. On the other hand, when the concentration of the n-type dopant (for example, Si) is high, it acts as a resistance when horizontally moving, so that the light-emitting efficiency of the photoelectron and the horizontal movement efficiency of electrons can be improved by adjoining the light-

14, the ESD protection layer 190 according to some embodiments may include a doped region, which may include at least one n-type dopant shock layer 195.

As shown, the ESD protection layer 190 may include an n-type dopant shock layer 195 doped with an n-type dopant in a relatively thin thickness region. The n-type dopant shock layer 195 may be formed to have a thickness smaller than that of the first to third doped regions 192, 193, and 194 described in the embodiment of FIG. 13, and further, Respectively. The n-type dopant shock layer 195 may be formed in a plurality of layers, and the plurality of n-type dopant shock layers 195 may be disposed in the ESD prevention layer 190 at regular intervals, or alternatively, 190, respectively. In addition, the plurality of n-type dopant shock layers 195 may be arranged to increase or decrease in spacing along the direction toward the light absorbing layer 150 side.

The doped regions 192, 193, 194 and 195 may be located in the ESD protection layer 190, as shown in FIG. 13 or 14, so that the doped regions 192, 193, 194, 195), undoped regions (undoped nitride based semiconductor layers) 191 may be disposed on the upper and lower portions of the semiconductor substrate. Thus, in the ESD protection layer 190, the undoped region 191 may be in contact with at least one of the low current blocking layer 140 and the first nitride layer 130.

By adding an undoped region between the doped regions, the photoelectrons lower the resistance to be introduced into the second electrode 173 during the operation of the device, and the depletion region is wider when ESD is applied.

Since the ESD prevention layer 190 includes an n-type dopant doped region, it is prevented by the doped region that the depletion layer is expanded by static electricity. Accordingly, the electrostatic discharge characteristic of the photodetecting device can be further improved. In addition, the resistance of the ESD prevention layer 190 is reduced by the doped region of the ESD prevention layer 190, so that the flow of current during the operation of the photodetector becomes smooth, and the light detection efficiency of the device can be improved.

The photodetecting device according to the above embodiments includes the low current blocking layer 140 and the ESD prevention layer 190 to prevent damage to the device due to static electricity or the like. Accordingly, the reliability of the photodetecting device can be reduced, and when the photodetecting device is applied to an actual application, it is possible to prevent an increase in the visible light response rate relative to the ultraviolet light according to the use of the application.

Experimental Example 2

14 is a graph for comparing characteristics of the photodetector according to another experimental example of the present invention.

In this experimental example, the embodiment is a photodetecting element having a configuration substantially similar to that of the photodetecting element of Fig. 10, and the comparative example is a photodetecting element having a configuration in which the ESD prevention layer 180 is omitted in the photodetecting element of Fig. 10 . In this experiment, photoresist retention ratios of the photodetecting devices according to Examples and Comparative Examples were measured by applying 100V, 200V, 300V, 400V and 500V stepwise with ESD voltage.

As shown in the graph of Fig. 14, in the case of the photodetecting device of the embodiment, almost 100% of the photoreaction is maintained even with the ESD voltage of 400V. On the other hand, in the case of the photodetecting device of the comparative example, it can be seen that the photoreaction decreases even by the ESD voltage of 200V, and the device is broken by the ESD voltage of 300V, and the photodetecting function is lost. As described above, according to the present experimental example, it can be seen that the photodetecting device including the ESD prevention layer does not break the device even by an ESD voltage twice or more as compared with the device not including the ESD prevention layer.

Experimental Example 3

Experiments were conducted to investigate the effective thickness of the ESD protection layer. The photodetecting device applied in this experiment example has a substrate, an n-type GaN first nitride layer of about 3 탆, a u-GaN ESD prevention layer, a light absorbing layer and a Ni Schottky contact layer. Further, the depth of the mesa exposing the n-type GaN first nitride layer was about 0.6 mu m, and the first electrode and the second electrode were formed on the Ni Schottky contact layer and the n-type GaN first nitride layer, respectively.

Table 1 shows the measurement results between the generated current and the ESD yield while increasing the thickness of the u-GaN ESD layer. The ESD yield according to the following ESD measurement results is the ratio of chips that are not shorted after 400V is applied to about 100 devices classified according to rank. The photocurrent is a measurement of the current generated when a voltage of 1 V is applied while irradiating the LED light of UV-B.

u-GaN thickness (nm) Photocurrent (nA) ESD yield (%) none 43.74 53.4 100 56.97 62.1 200 52.15 63.7 300 78.18 88.5 400 71.04 90.5 500 60.5 90.6

As shown in Table 1, when the thickness of the u-GaN ESD prevention layer is 300 nm or more, the ESD yield is greatly increased. It is analyzed that the n-type dopant reduces the mobility of electrons, and thus the ESD prevention layer is caused by the effect of horizontal dispersion of the photocurrent. However, when the ESD prevention layer is 300 nm, the photocurrent decreases. This is because u-GaN acts as a resistance element in terms of the vertical movement of electrons. The ESD yield sharply increases until the thickness of the ESD prevention layer is 400 nm, and the increase width is slowed at a thickness above that. The thickness of the u-GaN layer in the ESD prevention layer is the best in terms of ESD and photocurrent when the thickness of the ESD prevention layer is about 200 to 400 nm. Further, when the thickness of the ESD prevention layer is about 300 nm, . However, the present invention is not limited to the examples.

15 is a sectional view for explaining a light detecting element according to another embodiment of the present invention. The photodetecting device of this embodiment is substantially similar to the photodetecting device shown in Fig. 1, but differs in that the photodetecting device can be flip-bonded onto the secondary substrate 200. [ Hereinafter, the photodetecting device of this embodiment will be described mainly on the basis of the differences, and the detailed description of the same constitution will be omitted.

15, the photodetecting device includes a first nitride layer 130, a low current blocking layer 140, a light absorbing layer 150, and a Schottky bonding layer 160. Further, the photodetecting device may further include a first electrode 171 and a second electrode 173, and the photodetecting device may be flip-bonded on the secondary substrate 200 to form a photodetector package Can be provided. At this time, the secondary substrate 200 may include a base 210, a first lead electrode 221, and a second lead electrode 223, and the first and second electrodes 171 and 173 of the photo- May be electrically connected to the first and second lead electrodes 221 and 223 of the secondary substrate 200, respectively.

On the other hand, in the photodetecting device of this embodiment, the substrate 110 can be removed from the first nitride layer 130 as compared with the photodetecting device of Fig. The substrate 110 can be removed from the first nitride layer 130 using at least one of laser lift off, chemical lift off, thermal lift off, and stress lift off. In this regard, it will be described later in more detail with reference to FIG. 17 and FIG. However, the present invention is not limited thereto, and the substrate 110 may remain without being separated from the first nitride layer 130.

On the other hand, in the operation of the photodetector of this embodiment, the light to be irradiated can mainly be incident on the upper surface of the photodetector, that is, the upper surface of the first nitride layer 130. In order for the photodetecting device to operate smoothly, the incident light preferably passes through the first nitride layer 130 and reaches the light absorbing layer 150. Accordingly, the first nitride layer 130 may be formed of a nitride semiconductor containing Al at a predetermined concentration. Furthermore, in the case of a photodetector element for detecting ultraviolet light, the band gap energy of the first nitride layer 130 may be larger than the band gap energy of the light absorption layer 150. For example, when the photodetecting device of this embodiment is a photodetecting device that detects ultraviolet light in the UVB region, the first nitride layer 130 may include AlGaN having an Al composition ratio of about 28% or more. Accordingly, it is possible to minimize the absorption of light incident on the light detecting element into the first nitride layer 130 before reaching the light absorbing layer 150. However, the present invention is not limited thereto, and the composition and the composition ratio of the first nitride layer 130 may be variously adjusted according to the wavelength range of light to be detected by the photodetector.

16 is a cross-sectional view for explaining a light detecting element according to another embodiment of the present invention. The photodetecting device of this embodiment is substantially similar to the photodetecting device shown in Fig. 1, but differs in that the photodetecting device is vertically formed. Hereinafter, the photodetecting device of this embodiment will be described mainly on the basis of the differences, and the detailed description of the same constitution will be omitted.

16, the photodetecting device includes a first nitride layer 130, a low-current blocking layer 140, a light absorbing layer 150, and a Schottky bonding layer 160. Furthermore, the photodetecting device may further include a first electrode 171 and a second electrode 173.

1, the substrate 110 can be separated from the first nitride layer 130, and the second electrode 173 can be separated from the first nitride layer 130 by separating the substrate 110 from the first nitride layer 130. In this case, And may be located on the upper surface of the exposed first nitride layer 130. That is, the first electrode 171 and the second electrode 173 may be arranged vertically. The substrate 110 can be removed from the first nitride layer 130 using at least one of laser lift off, chemical lift off, thermal lift off, and stress lift off. In this regard, it will be described later in more detail with reference to FIG. 17 and FIG.

In the photodetecting device of this embodiment, similarly to the photodetecting device of Fig. 15, the light to be irradiated may mainly be incident on the upper surface of the photodetecting device, that is, the upper surface of the first nitride layer 130. [ Accordingly, the composition and the composition ratio of the first nitride layer 130 can be variously adjusted according to the wavelength band of light to be detected by the photodetector.

Hereinafter, with reference to FIGS. 17 and 18, a method of separating the substrate 110 using the laser lift-off method in manufacturing the photodetecting device according to the embodiment of FIGS. 15 and 16 will be described in more detail.

17 (a) shows a photodetecting device before the substrate 110 is separated. The photodetecting device includes a Schottky junction layer 160, a light absorption layer 150 disposed on the Schottky junction layer 160, a low current blocking layer 140 disposed on the light absorption layer 150, A first nitride layer 130 located on the low current blocking layer 140, a second nitride layer 120 located on the first nitride layer 130, and a substrate 110.

The second nitride layer 120 may include a buffer layer 121 and a compensation layer 123. The buffer layer 121 may be located below the lower surface of the substrate 110 and may include a nitride semiconductor containing Al of 1% or less. For example, the buffer layer 121 may be formed of GaN. The compensation layer 123 may mitigate stress due to the difference in lattice constant between the buffer layer 121 and the first nitride layer 130. The compensating layer 123 may include a nitride semiconductor having an Al composition ratio higher than that of the buffer layer 121 and having an Al composition ratio lower than that of the first nitride layer 130. [ Further, the compensating layer 123 may include a multi-layer or a composition-ratio gradient layer whose Al composition ratio increases along the direction from the buffer layer 121 to the first nitride layer 130.

When the substrate 110 is separated using the laser lift-off, a laser beam is irradiated from the upper surface of the substrate 110 downward. At this time, a KrF excimer laser is mainly used as the laser. However, when the KrF excimer laser has a wavelength of 248 nm and the second nitride layer 120 located between the substrate 110 and the first nitride layer 130 contains Al, (Not shown). This phenomenon can be exacerbated as the Al composition ratio of the second nitride layer 120 is higher. According to the present embodiment, the second nitride layer 120 includes a buffer layer 121 formed of, for example, GaN, which is substantially free of Al, so that a laser applied during laser lift-off is absorbed in the buffer layer 121 . Therefore, even if the KrF excimer laser is used, the substrate 110 can be easily separated, and the manufacturing process of the photodetecting device of this embodiment can be facilitated.

15 and 16, the first nitride layer 130 may include Al of a predetermined composition ratio depending on the wavelength band of light to be detected by the photodetector. In this case, have. When the buffer layer 121 is formed of GaN, a stress due to a difference in lattice constant between the buffer layer 121 and the first nitride layer 130 containing Al may be generated. When the stress is intensified, May increase and even cracks may occur. According to this embodiment, the compensation layer 123 is interposed on the buffer layer 121 and the first nitride layer 130 to relieve such stress and prevent the defect concentration from increasing in the first nitride layer 130 .

18, a laser L may be irradiated on the upper surface of the substrate 110 to separate the substrate 110 from the first nitride layer 130. Next, as shown in FIG. At this time, the substrate 110 may be separated from the second nitride layer 120, and may be separated from the buffer layer 121. After the removal of the substrate 110, the remaining second nitride layer 120 may be removed by dry etching, wet etching or a known cleaning process.

The above-described method of separating the substrate 110 can be applied to the manufacture of the photodetecting device of Figs. According to the present embodiment, the substrate 110 can be easily separated by applying the laser lift-off process, and the defect concentration of the first nitride layer 130 due to the buffer layer 121 for applying the laser lift- Can be prevented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Various variations and modifications are possible.

Claims (19)

A first nitride layer;
An ESD (Electrostatic Discharge) prevention layer located on the first nitride layer and including an undoped nitride based semiconductor;
A light absorption layer disposed on the ESD prevention layer;
A Schottky junction layer located on the light absorption layer; And
And a first electrode and a second electrode electrically connected to the Schottky junction layer and the first nitride layer, respectively,
Wherein the average n-type dopant doping concentration of the ESD prevention layer is lower than the average n-type dopant doping concentration of the first nitride layer.
The method according to claim 1,
The ESD protection layer includes at least one undoped nitride based semiconductor layer, and the undoped nitride based semiconductor layer has a total thickness of 300 nm to 400 nm.
The method according to claim 1,
And a low current blocking layer located between the ESD prevention layer and the light absorption layer and including a multilayer structure layer.
The method of claim 3,
Wherein the interlayer interfacial surface of the multilayer structure layer has a band gap larger than that of each layer.
The method according to claim 1,
Wherein the ESD protection layer comprises a doped region including an n-type dopant.
The method of claim 5,
Wherein the doped region comprises a first doped region, a second doped region located on the first doped region, and a third doped region located on the second doped region,
Wherein the doping concentration of the second doping region is higher than the doping concentration of the first doping region and the doping concentration of the third doping region is higher than the doping concentration of the second doping region.
The method of claim 6,
Wherein the first doped region is in contact with the second doped region and the second doped region is in contact with the third doped region.
The method of claim 6,
Wherein in the at least one of the first to third doped regions, the n-type dopant concentration increases, decreases, or has a modulation-doped profile along the direction toward the light absorbing layer side.
The method of claim 5,
Wherein the doped region comprises at least one n-type dopant shock region.
The method of claim 5,
And the undoped nitride-based semiconductor is located at the top and bottom of the doped region.
The method of claim 10,
And the undoped nitride based semiconductor of the ESD prevention layer is in contact with at least one of the low current blocking layer and the first nitride layer.
The method according to claim 1,
Wherein the light absorption layer comprises at least one of AlGaN and AlInGaN.
The method of claim 12,
Wherein the multilayer structure layer of the low current blocking layer comprises a superlattice structure in which an AlxGa (1-x) N layer and an AlyGa (1-y) N layer (x?
The method according to claim 1,
Wherein the low current blocking layer has a higher defect density than the light absorbing layer.
The method according to claim 1,
Further comprising a substrate positioned below the first nitride layer,
Wherein the first electrode is located on the Schottky junction layer and the second electrode is located on the first nitride layer and is in electrical contact.
The method according to claim 1,
And the light absorption layer is flip-bonded to the secondary substrate so as to face the bottom surface of the photodetecting device.
The method according to claim 1,
Wherein the light absorption layer is disposed to face the bottom surface of the photodetecting device,
Wherein the first electrode is located below the Schottky junction layer and the second electrode is located above the first nitride layer.
18. The method of claim 16,
Wherein a band gap energy of the first nitride layer is larger than a band gap energy of the light absorption layer.
18. The method of claim 17,
Wherein a band gap energy of the first nitride layer is larger than a band gap energy of the light absorption layer.

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