CN115000234B - NPN ultraviolet detector structure based on polarization doping - Google Patents

NPN ultraviolet detector structure based on polarization doping Download PDF

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CN115000234B
CN115000234B CN202210740678.8A CN202210740678A CN115000234B CN 115000234 B CN115000234 B CN 115000234B CN 202210740678 A CN202210740678 A CN 202210740678A CN 115000234 B CN115000234 B CN 115000234B
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npn
gradual change
ultraviolet detector
polarization
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CN115000234A (en
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张紫辉
宣展
楚春双
朱政吉
张勇辉
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Hebei University of Technology
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Abstract

The invention relates to an NPN ultraviolet detector structure based on polarization doping. The structure replaces the traditional P-type doping layer by introducing an Al component graded layer into the NPN ultraviolet photoelectric detector, and is characterized in that the Al component graded layer is arranged or not arranged in the Al y Ga 1‑y The structure of the N insertion layer obtains three NPN ultraviolet detector structures based on polarization doping. The invention realizes P-type doping by utilizing three-dimensional hole gas (3 DHG) generated by polarization effect, avoids extra acceptor impurities introduced into the device structure, leads electron current in the ultraviolet photoelectric detector to be dominant, and improves the response speed and the responsiveness of the device.

Description

NPN ultraviolet detector structure based on polarization doping
Technical Field
The invention relates to the field of semiconductor photoelectric detectors, in particular to an NPN ultraviolet detector structure based on polarization doping and a preparation method thereof, and belongs to the technical field of semiconductor photoelectronic devices.
Background
The photoelectric detector plays a role of converting an optical signal into an electric signal in an optical communication system, and has important application value in military and civil fields such as missile early warning, fire monitoring, public security investigation, environment detection and the like. In recent years, with the continuous development and perfection of semiconductor materials and component preparation processes thereof, ultraviolet detectors with PN/PIN structures based on wide bandgap semiconductor materials have attracted research interests of a large number of researchers.
The currently dominant ultraviolet detector types are silicon (1.1 eV) based ultraviolet detectors, alGaN (3.4 eV-6.2 eV) based ultraviolet detectors, mgZnO (3.3 eV-7.8 eV) based ultraviolet detectors and 4H-SiC (3.26 eV) based ultraviolet detectors. Among the common photodetector structures are: metal-semiconductor-metal (MSM) structures, PN/PIN structures, avalanche Photodetector (APD) structures. Ultraviolet detectors, regardless of material and construction, are intended to increase the sensitivity of detection by improving the responsivity of the detector to a particular wavelength. For this reason, researchers have conducted a series of studies. For example, chinese patent No. CN109346551a discloses a method for preparing an ultraviolet photoelectric detector based on AlGaN, which introduces a polarized electric field to make the detector generate more free carriers during operation, and accelerates the movement of the free carriers to increase the sensitivity of the detector; the patent carries out P type doping on AlGaN, but the high Al component AlGaN material has the problems of increased resistivity, low carrier mobility and poor ohmic contact of the P type AlGaN material due to the difficult P type doping, and finally the detection performance of the device is reduced. The chinese patent of CN109378361a discloses a method for realizing avalanche multiplication of AlGaN detector under low voltage, which uses P-type and N-type layers with graded Al composition to replace the conventional fixed Al composition P-type and N-type layers, and aims to introduce polarized charges to generate a strong electric field to enhance avalanche multiplication, but also needs to intentionally dope the material layers, and because of larger difference of Al composition values, the realization of gradual change process needs to be processed by a plurality of gradient cooling modes.
Fig. 1 of the accompanying drawings shows an ultraviolet photodetector of NPN structure comprising, in order along the epitaxial growth direction, a substrate (101), a buffer layer (102), a transport layer (103), a P-type hole-providing layer (105), an N-type electron-providing layer (106), a cathode electrode (107) and an anode electrode (108); wherein the P-type hole providing layer (105) is an AlGaN layer ionization-doped with conventional impurities, wherein the Al composition value is 0.2, and the doping concentration is 1×10 17 cm -3 The main disadvantage of this structure is that when n-GaN is grown on p-AlGaN, a relatively poor crystal quality will be obtained, affecting the performance of the detector.
Disclosure of Invention
The invention aims to provide an NPN ultraviolet detector structure based on polarization doping aiming at the technical defects of the current PIN ultraviolet photoelectric detector. According to the invention, the Al component graded layer is introduced into the NPN type ultraviolet photoelectric detector to replace the traditional P type doped layer, namely, the P type doping is realized by utilizing three-dimensional hole gas (3 DHG) generated by polarization effect, so that extra acceptor impurities introduced into the device structure are avoided, the electron current in the ultraviolet photoelectric detector is dominant, and the response speed and the response degree of the device are improved.
The technical scheme adopted by the invention for solving the technical problems is as follows:
an NPN ultraviolet detector structure based on polarization doping comprises the following three types:
the first one, the said structure includes substrate, buffer layer, transport layer sequentially along the direction of epitaxial growth; the middle part of the upper surface of the transmission layer is a strip-shaped exposed part, the rest part is covered with an Al component gradual change layer, the Al component gradual change layer is covered with an N-type electron providing layer, and both sides of the N-type electron providing layer are distributed with a cathode electrode and an anode electrode;
or the second kind, the structure sequentially comprises a substrate, a buffer layer, a transmission layer and Al along the epitaxial growth direction y Ga 1-y An N insertion layer; al (Al) y Ga 1-y The middle part of the upper surface of the N insertion layer is a strip-shaped exposed part, the rest part is covered with an Al component gradual change layer, an N-type electron providing layer is covered on the Al component gradual change layer, and cathode electrodes and anode electrodes are distributed on two sides of the N-type electron providing layer;
or, the third structure comprises a substrate, a buffer layer and a transmission layer in sequence along the epitaxial growth direction; the transmission layer is composed of an upper part and a lower part, and the middle part is Al y Ga 1-y An N insertion layer; the middle part of the upper surface of the upper transmission layer is a strip-shaped exposed part; the rest part is covered with an Al component gradual change layer, an N-type electron providing layer is covered on the Al component gradual change layer, and cathode electrodes and anode electrodes are distributed on two sides of the N-type electron providing layer;
the Al component gradual change layer is made of intrinsic Al x Ga 1-x N, the thickness is 0.005 mu m-0.5 mu m, wherein x is the gradual change range of Al components from x1 to x2, and the gradual change mode is as follows: from bottom to top, the Al component of the graded layer decreases in value from x1 to x2, 1>x1>x2 is more than or equal to 0; preferably x1 is not more than 0.7, x2 is not less than 0, and x1>x2。
Al of the second and third kind y Ga 1-y In the N insertion layer, the value of y is in the range of 0-1, and the thickness is in the range of 0.005-0.5 mu m.
The width of the exposed part in the first, second and third type is 0.01 μm to 100 μm.
The Al component gradual change layers at two sides of the exposed part in the first, second and third types are bilaterally symmetrical;
the substrate is specifically sapphire, silicon carbide or gallium nitride;
the buffer layer is made of AlN and has a thickness of 0.01-2 mu m;
the material of the transmission layer is unintentionally doped GaN, and the thickness is 0.1-5 mu m;
the material of the N-type electron supply layer is N-type doped GaN, and the thickness is 0.005 mu m-0.5 mu m.
The cathode electrode and the anode electrode are made of Cr/Au, ti/Au or Ni/Au.
The beneficial effects of the invention are as follows:
(1) According to the invention, the negative electrode body charge formed by the Al component gradual change layer (105) generates three-dimensional hole gas (3 DHG), so that the P-type doping effect is realized, the traditional P-type impurity ionization doping mode is replaced, and the problem of reduced conductivity of the device caused by difficult P-type impurity doping and lower acceptor ionization efficiency is effectively avoided; meanwhile, the electron current in the detector is dominant, and researches show that the effective mass of holes in the GaN material is larger than that of electrons, and the mobility of electrons is larger than that of holes under the same condition, so that the response speed of the detector with the dominant electron current is also faster, and the response speed of the detector is effectively improved.
(2) Al designed by the invention y Ga 1-y The heterostructure interface of the N insertion layer (104)/the transmission layer (103) can form positive polarization surface charges, so that a large amount of electrons are gathered, namely two-dimensional electron gas (2 DEG) is generated, and a high-speed transmission channel of electrons is formed; meanwhile, the heterostructure can also improve the height of the conduction band barrier, and dark current is effectively reduced. It can be seen from fig. 9 that at 10V bias, the polarization doped NPN ultraviolet detector structure has an order of magnitude higher photocurrent than the conventional impurity doped NPN ultraviolet detector structure; minimum value of dark current of polarized doped NPN ultraviolet detector structure and traditional impurity doped NThe PN ultraviolet detector structure is reduced by five orders of magnitude. Therefore, compared with the traditional structure, the responsivity of the polarized doped NPN ultraviolet detector structure is effectively improved.
(3) The operation process in the preparation method of the NPN ultraviolet detector structure based on polarization doping is provided by a person skilled in the art, the related raw materials can be obtained through a general way, the process is simple and reliable, the repeatability is high, the production cost is low, and the preparation method is suitable for industrial popularization and can be applied to the field of ultraviolet detection.
Drawings
FIG. 1 is a schematic diagram of a conventional impurity doped NPN ultraviolet detector;
FIG. 2 is a schematic diagram of a first polarization doping-based NPN ultraviolet detector in example 1;
FIG. 3 is a schematic diagram of a second polarization doping-based NPN ultraviolet detector in example 2;
FIG. 4 is a schematic diagram of a third polarization doping-based NPN ultraviolet detector in example 3;
FIG. 5 is a schematic diagram of epitaxial growth of the polarization doped NPN ultraviolet detector structure in example 1;
FIG. 6 is a schematic diagram of a structure of the NPN ultraviolet detector structure based on polarization doping in FIG. 5 after epitaxial growth to etch grooves;
FIG. 7 is a schematic diagram of epitaxial growth of the polarization doped NPN ultraviolet detector structure in example 2;
FIG. 8 is a schematic diagram of a structure of the NPN ultraviolet detector structure based on polarization doping in FIG. 7 after epitaxial growth;
FIG. 9 is a photo-dark current contrast plot of a polarization doped NPN UV detector structure versus a conventional P-doped NPN UV detector structure; fig. 9 (a) is a dark current comparison chart of the NPN ultraviolet detector structure based on polarization doping and the NPN ultraviolet detector structure based on conventional impurity doping in the embodiment 1 and the embodiment 2; FIG. 9 (b) is a graph showing comparison of photocurrents of two polarization doped NPN ultraviolet detectors and a conventional impurity doped NPN ultraviolet detector structure in embodiment 1 and embodiment 2;
FIG. 10 is a graph showing the contrast of light and dark current when the intercalating layer is placed in different positions in a polarization doped UV detector plus intercalating layer structure; fig. 10 (a) is a dark current comparison chart of an NPN ultraviolet detector based on polarization doping in embodiment 2 and an NPN ultraviolet detector based on polarization doping in embodiment 3; fig. 10 (b) is a photo-current comparison chart of an NPN ultraviolet detector based on polarization doping in embodiment 2 and an NPN ultraviolet detector based on polarization doping in embodiment 3.
Wherein, 101. Substrate, 102. Buffer layer, 103. Transmission layer, 104.Al y Ga 1-y N insertion layer, 105.Al composition graded layer, 106.N type electron supply layer, 107. Cathode electrode, 108. Anode electrode.
Detailed Description
The invention is further described below with reference to examples and figures, which are not intended to limit the scope of the claims of the present application.
Example 1
An NPN ultraviolet detector structure based on polarization doping according to this embodiment can be seen in fig. 2, fig. 5, and fig. 6:
the embodiment shown in fig. 2 shows that the present patent discloses an NPN ultraviolet detector structure based on polarization doping, which comprises a substrate 101, a buffer layer 102, and a transmission layer 103 in sequence along the epitaxial growth direction; the middle part of the upper surface of the transmission layer 103 is a strip-shaped exposed part, the rest part is covered with an Al component gradual change layer 105, the Al component gradual change layer 105 is covered with an N-type electron supply layer 106, and cathode electrodes 107 and anode electrodes 108 are distributed on two sides of the N-type electron supply layer 106;
the Al component gradual change layers 105 on the two sides of the exposed part are bilaterally symmetrical;
the embodiment shown in fig. 5 shows that in this embodiment, an epitaxial wafer structure schematic diagram of an NPN ultraviolet detector structure based on polarization doping is fabricated on a substrate 101 by an epitaxial technology, and the structure includes: a substrate 101, a buffer layer 102, a transport layer 103, an Al composition gradient layer 105, an N-type electron supply layer 106;
the embodiment shown in fig. 6 shows that in this embodiment, on the basis of the structure obtained in fig. 5, an epitaxial wafer structure schematic diagram of an ultraviolet detector mesa is manufactured by a dry etching process, which is characterized in that a gap is etched in the middle area of the N-type electron supply layer 106 and the Al composition graded layer 105 until the upper surface of the transmission layer 103 is exposed, so that the device mesa forms a laterally symmetrical "concave" structure, and the structure includes: a substrate 101, a buffer layer 102, a transport layer 103, an Al composition gradient layer 105, an N-type electron supply layer 106;
the top view of the device structure in the patent can be square, rectangular, circular and other structures, the longitudinal sectional view is shown in fig. 2, the size is not limited, the micron-level or millimeter-level device can be prepared, and the exposed strip-shaped gap part is communicated from front to back. The top view of the device in this embodiment is rectangular, the horizontal total width of the device is 201 μm, the width of the exposed portion is 1 μm, and the widths of the Al composition graded layers 105 on both sides of the left and right symmetry are 100 μm;
the substrate 101 in the polarization doping-based NPN ultraviolet detector structure uses sapphire; the material of the buffer layer 102 is AlN, and the thickness is 0.2 μm; the cathode electrode 107 and the anode electrode 108 are made of Ni/Au;
the material of the transmission layer 103 is unintentionally doped GaN, and the thickness is 0.5 μm;
the Al composition gradient layer 105 is made of unintentionally doped Al x Ga 1-x N, wherein x is the gradual change range of the Al component from x1 to x2, and the gradual change mode is as follows: from bottom to top, in the composition of the gradation layer, the value of the Al composition decreases from x1 to x2, x being an Al composition gradation range in which x1=0.27 to x2=0, and the thickness thereof is 0.05 μm;
the N-type electron supply layer 106 is made of N-type doped GaN with a doping concentration of 3.5X10 18 cm -3 The thickness was 0.15. Mu.m.
The preparation method of the NPN ultraviolet photoelectric detector structure based on polarization doping comprises the following steps:
1) Using MOA CVD or HVPE method of epitaxially growing a buffer layer 102 on the surface of the sapphire substrate 101 at 1050 ℃ and 50mbar of air pressure, thereby filtering dislocation defects and releasing stress generated by lattice mismatch; continuing to epitaxially grow the transmission layer 103, the Al component gradient layer 105 and the N-type electron supply layer 106, wherein the growth temperature is 1050 ℃, and the air pressure is 50mbar; the Al composition gradient layer 105 is prepared by using trimethylgallium (TMGa), trimethylaluminum (TMAL) and ammonia (NH) 3 ) As precursors of Ga, al and N, hydrogen (H 2 ) As a carrier gas. The Al content value of the graded layer is designed by adjusting the Al/Ga precursor ratio, thereby achieving the graded effect of the Al composition graded layer 105 from 0.27 for the bottom Al composition to 0 for the upper surface Al composition. (see FIG. 5 for this procedure)
2) Etching the epitaxial structure by photoetching and dry etching processes, wherein the mesa etching utilizes an Inductively Coupled Plasma (ICP) etching technology, and the etching gas is Cl 2 With BCl 3 The method comprises the steps of carrying out a first treatment on the surface of the The etching width of the strip-shaped exposed part in the middle of the upper surface of the transmission layer 103 is 1 μm, and the etching depth reaches the upper surface of the transmission layer 103; (see FIG. 6 for this procedure)
3) The cathode electrode 107 and the anode electrode 108 are manufactured by using a photoetching technology and an e-beam evaporation process. (see FIG. 2 for this procedure)
Fig. 9 shows the performance index of the photo-dark current in this example, in which "polarization doped NPN ultraviolet detector" corresponds to the device structure prepared in example 1, and "polarization doped NPN ultraviolet detector with insertion layer" corresponds to the device structure prepared in example 2. The conventional impurity doped NPN ultraviolet detector corresponds to the comparison device in the attached figure 1. Under the condition that the applied voltage is 10V, the photocurrent of the NPN ultraviolet detector based on polarization doping is improved by about ten times compared with that of the NPN ultraviolet detector based on traditional doping, and dark current is basically consistent with that of the traditional structure, so that the problem that the device P type impurity doping is difficult and the acceptor ionization efficiency is low is avoided due to the fact that negative electrode body charges formed by a graded layer in the structure of the NPN ultraviolet detector based on polarization doping attract a large number of holes to generate 3 DHG. Therefore, under the illumination condition, the NPN ultraviolet detector based on polarization doping improves the photocurrent of the device by virtue of efficient P-type doping.
Example 2
The preparation steps of an NPN ultraviolet photodetector structure based on polarization doping in this embodiment are shown in FIG. 3, FIG. 7 and FIG. 8, and are different from embodiment 1 in that Al is added in this embodiment y Ga 1-y N insertion layer 104:
the embodiment shown in fig. 3 shows that in this embodiment, the present patent discloses an NPN ultraviolet detector structure based on polarization doping, which sequentially includes a substrate 101, a buffer layer 102, a transmission layer 103, and Al along the epitaxial growth direction y Ga 1-y N insertion layer 104; al (Al) y Ga 1-y The middle part of the upper surface of the N insertion layer 104 is a strip-shaped exposed part, the rest part is covered with an Al component gradual change layer 105, the Al component gradual change layer 105 is covered with an N-type electron supply layer 106, and cathode electrodes 107 and anode electrodes 108 are distributed on two sides of the N-type electron supply layer 106;
the Al component gradual change layers 105 on the two sides of the exposed part are bilaterally symmetrical;
the exposed strip-shaped gap part is through from front to back, the top view of the device in the embodiment is rectangular, the longitudinal sectional view is shown in fig. 3, the horizontal total width of the device is 201 μm, the width of the exposed part is 1 μm, and the widths of the Al component gradient layers 105 on two sides which are bilaterally symmetrical are 100 μm;
the embodiment shown in fig. 7 shows that in this embodiment, the present patent discloses an NPN ultraviolet detector structure based on polarization doping, which sequentially includes a substrate 101, a buffer layer 102, a transmission layer 103, and Al along the epitaxial growth direction y Ga 1-y An N insertion layer 104, an Al composition gradient layer 105, and an N-type electron supply layer 106;
the embodiment shown in fig. 8 shows that in this embodiment, the epitaxial wafer structure schematic diagram of the ultraviolet detector mesa is fabricated on the structure obtained in fig. 7 by a dry etching process, and is characterized in that the intermediate regions of the N-type electron supply layer 106 and the Al composition graded layer 105 are etched to expose Al y Ga 1-y The upper surface of the N insertion layer 104 forms a laterally symmetrical "concave" structure on the device mesa, which includes:substrate 101, buffer layer 102, transport layer 103, al y Ga 1-y An N insertion layer 104, an Al composition gradient layer 105, and an N-type electron supply layer 106;
the substrate 101 in the polarization doping-based NPN ultraviolet detector structure uses sapphire; the material of the buffer layer 102 is AlN, and the thickness is 0.2 μm; the method comprises the steps of carrying out a first treatment on the surface of the The cathode electrode 107 and the anode electrode 108 are made of Ni/Au;
the material of the transmission layer 103 is undoped GaN, and the thickness is 0.5 μm;
the Al composition gradient layer 105 is made of unintentionally doped Al x Ga 1-x N, where x is an Al composition gradient range ranging from x1=0.27 to x2=0, and the thickness thereof is 0.05 μm; the N-type electron supply layer 106 is made of N-type doped GaN with a doping concentration of 3.5X10 18 cm -3 The thickness was 0.15. Mu.m.
In the polarized doping-based NPN ultraviolet photoelectric detector structure, unintended doping Al is added between the transmission layer 103 and the Al component graded layer 105 y Ga 1-y N insertion layer 104, where y has a value of 0.27, is located on the upper surface of the transfer layer 103 and has a thickness of 0.01 μm. Addition of Al under the Al composition-graded layer 105 y Ga 1-y After N is inserted into layer 104, the conduction band barrier height in the band structure of the device will become higher and the blocking effect on electrons will become stronger to obtain lower dark current.
The preparation method of the NPN ultraviolet photoelectric detector structure based on polarization doping comprises the following steps:
1) A buffer layer 102 is epitaxially grown on the surface of the sapphire substrate 101 by using an MOCVD or HVPE method, wherein the growth temperature is 1050 ℃ and the air pressure is 50mbar, so that dislocation defects are filtered and stress generated by lattice mismatch is released; continuing epitaxial growth of the transport layer 103, al y Ga 1-y An N insertion layer 104, an Al composition gradient layer 105 and an N-type electron supply layer 106, wherein the growth temperature is 1050 ℃, and the air pressure is 50mbar; (see FIG. 7 for this procedure)
2) Etching the epitaxial structure by photolithography and dry etching processes, and mesa etching using Inductively Coupled Plasma (ICP) etchingTechnology, etching gas is Cl 2 With BCl 3 . Etching width is 1 μm, etching depth is up to upper surface of the interposer 104; (see FIG. 8 for this procedure)
3) The cathode electrode 107 and the anode electrode 108 are manufactured by using a photoetching technology and an e-beam evaporation process. (see FIG. 3 for this procedure)
Fig. 9 shows the performance index of the photo-dark current in this example, in which "polarization doped NPN ultraviolet detector" corresponds to the device structure prepared in example 1, and "polarization doped NPN ultraviolet detector with insertion layer" corresponds to the device structure prepared in example 2. The conventional impurity doped NPN ultraviolet detector corresponds to the comparison device in the attached figure 1. As can be seen from the figure, under the condition of applying small voltage to the device, the dark current of the structure added with the insertion layer is smaller, and the photocurrent is basically consistent, because of the addition of the insertion layer, the barrier height in the energy band structure of the device is improved, electrons are difficult to cross the barrier under the condition of not applying small bias voltage of light, and the dark current is effectively reduced.
Example 3
The preparation steps of an NPN ultraviolet photodetector structure based on polarization doping in this embodiment are the same as those in embodiment 2, and are different from those in embodiment 2 in that Al in this embodiment y Ga 1-y The N insertion layer is located in the middle of the transport layer 103 (see fig. 4 for this embodiment):
the embodiment shown in fig. 4 shows that in this embodiment, the present patent discloses an NPN ultraviolet detector structure based on polarization doping, which includes a substrate 101, a buffer layer 102, and a transmission layer 103 in order along an epitaxial growth direction; the transmission layer 103 is composed of an upper part and a lower part, and Al is arranged in the middle y Ga 1-y N insertion layer 104; the middle part of the upper surface of the upper transmission layer 103 is a strip-shaped exposed part; the rest part is covered with an Al component gradual change layer 105, an N-type electron supply layer 106 is covered on the Al component gradual change layer 105, and cathode electrodes 107 and anode electrodes 108 are distributed on two sides of the N-type electron supply layer 106;
the Al component gradual change layers 105 on the two sides of the exposed part are bilaterally symmetrical;
the exposed strip-shaped gap part is through from front to back, the top view of the device in the embodiment is rectangular, the longitudinal sectional view is shown in fig. 4, the horizontal total width of the device is 201 μm, the width of the exposed part is 1 μm, and the widths of the Al component gradient layers 105 on two sides which are bilaterally symmetrical are 100 μm;
in the polarized doping-based NPN ultraviolet photoelectric detector structure, unintended doping Al is added between the transmission layer 103 and the Al component graded layer 105 y Ga 1-y An N insertion layer 104, where y has a value of 0.2, is located in the middle region of the transport layer 103 at a distance of 0.3 μm from the lower buffer layer 102 and 0.2 μm from the upper Al composition gradient layer 105, al y Ga 1-y The thickness of the N-interposed layer 104 is 0.01 μm.
The preparation method of the NPN ultraviolet photoelectric detector structure based on polarization doping comprises the following steps:
1) A buffer layer 102 is epitaxially grown on the surface of the sapphire substrate 101 by using an MOCVD or HVPE method, wherein the growth temperature is 1050 ℃ and the air pressure is 50mbar, so that dislocation defects are filtered and stress generated by lattice mismatch is released; continuing epitaxial growth of the transport layer 103, al y Ga 1-y The N insertion layer 104, the transmission layer 103, the Al component gradual change layer 105 and the N type electron supply layer 106 are grown at 1050 ℃ and the air pressure is 50mbar;
2) Etching the epitaxial structure by photoetching and dry etching processes, wherein the mesa etching utilizes an Inductively Coupled Plasma (ICP) etching technology, and the etching gas is Cl 2 With BCl 3 . Etching width of 1 μm and etching depth of Al y Ga 1-y N interposers 104 on the upper surface of the transport layer 103.
3) The cathode electrode 107 and the anode electrode 108 are manufactured by using a photoetching technology and an e-beam evaporation process. (see FIG. 4 for this procedure)
In fig. 10, "the interposer moves down to the middle of the transport layer" is the structure of this embodiment, and "the interposer is on the upper surface of the transport layer" is the structure of embodiment 2. The performance index of the photo-dark current in this embodiment is shown, from which it can be seen that by changing the position of the insertion layer, the photo-current is slightly increased and the dark current is reduced by four orders of magnitude with a bias voltage of 5V. This is because when the insertion layer moves down to the middle portion of the transport layer, alGaN material used for the insertion layer has a smaller dielectric constant than GaN transport layer, and the thickness of the insertion layer is thin, a stronger built-in electric field is formed in the insertion layer, functioning as an electron blocking layer, and thus the blocking barrier formed in the transport layer effectively reduces dark current of the device. The barrier height is reduced after light is added, and meanwhile, the two-dimensional electron gas channel formed by the lower surface of the insertion layer and the transmission layer is conducted, so that the mobility of electrons is improved, and the effect of improving photocurrent is achieved.
The NPN ultraviolet detector structure based on polarization doping in the embodiments can be realized, and has a certain influence on the light dark current of the detector, so that the detection responsiveness is improved. The responsivity and the light dark current are directly related, and the calculation formula is as follows: responsivity= (photocurrent-dark current)/incident light power, when the incident light power keeps consistent, the responsivity is improved by how much to directly pass through the ratio of 'photocurrent-dark current'. Under the bias condition of 10V, the photoelectric value of the polarized doped NPN ultraviolet detector is about 11mA, the dark current is about 0.1mA, and the photoelectric value of the traditional P-type doped ultraviolet detector is about 1mA, and the dark current is about 0.1mA, so that the responsivity of the polarized doped NPN ultraviolet detector structure is improved ten times than that of the traditional structure.
In addition, the effect of the ultraviolet detector based on polarization doping is affected by the material and dimensional change of the transmission layer, the insertion layer, the Al component gradual change layer and the N-type electron supply layer in the detector, so that the ultraviolet detector based on polarization doping has the best effect because the ultraviolet detector based on polarization doping needs to be properly optimized according to different device structures and different technological methods.
The above examples are only preferred embodiments of the present invention, it being noted that: it will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles of the present invention, and these equivalents should be substituted for the claims set forth herein without departing from the scope of the invention as defined by the appended claims and their equivalents.
The invention is not a matter of the known technology.

Claims (5)

1. The NPN ultraviolet detector structure based on polarization doping is characterized by comprising the following three structures:
the first one, the said structure includes substrate, buffer layer, transport layer sequentially along the direction of epitaxial growth; the middle part of the upper surface of the transmission layer is a strip-shaped exposed part, the rest part is covered with an Al component gradual change layer, the Al component gradual change layer is covered with an N-type electron providing layer, and both sides of the N-type electron providing layer are distributed with a cathode electrode and an anode electrode;
or the second kind, the structure sequentially comprises a substrate, a buffer layer, a transmission layer and Al along the epitaxial growth direction y Ga 1-y An N insertion layer; al (Al) y Ga 1-y The middle part of the upper surface of the N insertion layer is a strip-shaped exposed part, the rest part is covered with an Al component gradual change layer, an N-type electron providing layer is covered on the Al component gradual change layer, and cathode electrodes and anode electrodes are distributed on two sides of the N-type electron providing layer;
or, the third structure comprises a substrate, a buffer layer and a transmission layer in sequence along the epitaxial growth direction; the transmission layer is composed of an upper part and a lower part, and the middle part is Al y Ga 1-y An N insertion layer; the middle part of the upper surface of the upper transmission layer is a strip-shaped exposed part; the rest part is covered with an Al component gradual change layer, an N-type electron providing layer is covered on the Al component gradual change layer, and cathode electrodes and anode electrodes are distributed on two sides of the N-type electron providing layer;
the Al component gradual change layer is made of intrinsic Al x Ga 1-x N, the thickness is 0.005 mu m-0.5 mu m, wherein x is the gradual change range of Al components from x1 to x2, and the gradual change mode is as follows: from bottom to top, the Al component of the graded layer decreases in value from x1 to x2, 1>x1>x2≥0；
Al of the second and third kind y Ga 1-y In the N insertion layer, the value of y is in the range of 0-1, and the thickness is in the range of 0.005-0.5 mu m.
2. The polarization-doped NPN ultraviolet detector structure of claim 1, wherein the width of the exposed portions of the first, second and third types is 0.01 μm to 100 μm.
3. The polarization-doped NPN ultraviolet detector structure of claim 1 wherein the graded layers of Al composition on both sides of the exposed portions of the first, second and third species are side-to-side symmetric.
4. The polarization doping-based NPN ultraviolet detector structure of claim 1, wherein the substrate is specifically sapphire, silicon carbide or gallium nitride;
the buffer layer is made of AlN and has a thickness of 0.01-2 mu m;
the material of the transmission layer is unintentionally doped GaN, and the thickness is 0.1-5 mu m;
the material of the N-type electron supply layer is N-type doped GaN, and the thickness is 0.005 mu m-0.5 mu m;
the cathode electrode and the anode electrode are made of Cr/Au, ti/Au or Ni/Au.
5. The polarization doping-based NPN ultraviolet detector structure as claimed in claim 1, wherein said Al composition graded layer material is intrinsic Al x Ga 1-x In N, preferably, x1 is not more than 0.7, x2 is not less than 0, and x1>x2。
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* Cited by examiner, † Cited by third party
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Title
利用紫外透射光谱研究透射式GaN光电阴极的材料结构及光学特性;杜晓晴;田健;周强富;;光谱学与光谱分析(第06期);全文 *

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