Deep ultraviolet LED device

Abstract

The utility model provides a deep ultraviolet LED device, which comprises an MESA mesa layer with a concave part, the concave part does not completely penetrate through the MESA mesa layer, a plurality of N-type contact sub-electrodes which are arranged at intervals are deposited on the bottom surface of the concave part, the N-type contact sub-electrodes form an N-type electrode area, the deep ultraviolet LED device further comprises a P-type contact electrode, and the P-type contact electrode is arranged on the bottom surface of the concave part. The P-type contact electrode is arranged on the top surface of the MESA mesa layer and is located outside the N-type electrode area; according to the deep ultraviolet LED device, a traditional N-type contact electrode is divided into a plurality of independent individual N-type contact sub-electrodes, and the P-type contact electrode is located outside the N-type electrode area formed by the N-type contact sub-electrodes, so that current expansion channels of the deep ultraviolet LED device are increased, the current congestion effect of the deep ultraviolet LED device is relieved, and the service life of the deep ultraviolet LED device is prolonged. And thus, the light extraction efficiency of the deep ultraviolet LED device is improved.

Description

Technical Field

[0001] The utility model relates to the field of semiconductor optoelectronics, in particular to a deep ultraviolet LED device. Background Art

[0002] In ultraviolet light, light with a wavelength of 200 nanometers to 350 nanometers is called deep ultraviolet light. AlGaN-based ultraviolet light emitting diode (LED) devices have received continuous attention due to their wide application prospects in air purification, sterilization, ultraviolet light therapy, biochemical detection, confidential communications and other fields. However, existing ultraviolet LED devices have the following problems: First, the existing ultraviolet LED devices have low light extraction efficiency, high voltage, and low photoelectric conversion efficiency; second, the existing ultraviolet LED devices will cause local current congestion due to incompatible electrode structures and electrode layout designs. On the one hand, local overheating will cause metal electromigration, material aging, etc., accelerate device degradation and cause chip failure. On the other hand, it will cause uneven light emission of ultraviolet LED devices and a decrease in light output power.

[0003] Therefore, there is an urgent need for a deep ultraviolet LED device to solve the above technical problems. Utility Model Content

[0004] The utility model aims to provide a deep ultraviolet LED device, which is used to improve the technical problem of low light extraction power caused by local current congestion in the deep ultraviolet light emitting diodes in the prior art.

[0005] In order to solve the above technical problems, the utility model provides a deep ultraviolet LED device, comprising a MESA mesa layer having a concave portion, the concave portion does not completely penetrate the MESA mesa layer, a plurality of N-type contact sub-electrodes spaced from each other are deposited on the bottom surface of the concave portion, and the plurality of N-type contact sub-electrodes form an N-type electrode region;

[0006] The deep ultraviolet LED device further includes a P-type contact electrode, which is arranged on the top surface of the MESA mesa layer and outside the N-type electrode region.

[0007] Preferably, the shortest distance between any two N-type contact sub-electrodes is less than or equal to the current extension length of the deep ultraviolet LED device.

[0008] Preferably, the recess comprises a plurality of groove groups staggered along a first direction, the groove groups comprising a first sub-groove, a second sub-groove and a third sub-groove sequentially arranged along a second direction, and the second direction is perpendicular to the first direction;

[0009] The bottom surfaces of the first sub-groove and the third sub-groove are circular, and the bottom surface of the second sub-groove is elliptical.

[0010] Preferably, the intervals between two adjacent groove groups are equal; within the same groove group, the first interval between the second sub-groove and the first sub-groove is equal to the second interval between the second sub-groove and the third sub-groove.

[0011] Preferably, the edge line width spacing between the N-type contact sub-electrode and the MESA mesa layer is 3-10 um.

[0012] Preferably, the edge line width spacing between the P-type contact electrode and the MESA mesa layer is 3-15 um.

[0013] Preferably, the deep ultraviolet LED device further comprises a first passivation layer, and the first passivation layer is deposited on the N-type contact electrode and the P-type contact electrode respectively;

[0014] The deep ultraviolet LED device further comprises a first passivation layer, which is deposited on the N-type contact electrode and the P-type contact electrode respectively, and the first passivation layer is provided with a first through hole and a second through hole at a position corresponding to the concave portion on the MESA mesa layer;

[0015] Among them, the bottom area of ​​the first through hole is smaller than the bottom area of ​​the first sub-groove or the third sub-groove, and the bottom area of ​​the second through hole is smaller than the bottom area of ​​the second sub-groove; the edge line width spacing between the first passivation layer and the N-type contact sub-electrode is 2~15um.

[0016] Preferably, the deep ultraviolet LED device further comprises a plurality of connection electrodes arranged at intervals, and a plurality of N-type contact sub-electrodes corresponding to the same groove group are electrically connected via one connection electrode;

[0017] The orthographic projection of the connecting electrode on the substrate is elliptical.

[0018] Preferably, the deep ultraviolet LED device further includes an N-type pad electrode and a P-type pad electrode, the N-type pad electrode is electrically connected to the N-type contact sub-electrode through a first passivation opening, and the P-type pad electrode is electrically connected to the P-type contact electrode through a second passivation opening.

[0019] Preferably, the distance between the N-type pad electrode and the P-type pad electrode is 50-200 um.

[0020] The beneficial effects of the utility model are as follows: different from the prior art, the utility model provides a deep ultraviolet LED device, including a MESA table layer with a concave portion, the concave portion does not completely penetrate the MESA table layer, a plurality of N-type contact sub-electrodes arranged at intervals from each other are deposited on the bottom surface of the concave portion, and the plurality of N-type contact sub-electrodes form an N-type electrode region, wherein the deep ultraviolet LED device also includes a P-type contact electrode, which is arranged on the top surface of the MESA table layer and is located outside the N-type electrode region; the utility model divides the traditional N-type contact electrode into a plurality of independent N-type contact sub-electrodes, and makes the P-type contact electrode located between the plurality of N-type contact sub-electrodes The N-type electrode area formed by the pole is outside the N-type contact sub-electrode area, thereby increasing the current expansion channel of the deep ultraviolet LED device, alleviating the current congestion effect of the deep ultraviolet LED device, and further improving the light extraction efficiency of the deep ultraviolet LED device; at the same time, the utility model forms 3 N-type contact sub-electrodes in each groove group. Compared with only forming two N-type contact sub-electrodes in each groove group, the number of N-type contact sub-electrodes of the deep ultraviolet LED device in each groove group is increased, thereby increasing the current expansion channel of the deep ultraviolet LED device in each groove group, alleviating the current congestion effect of the deep ultraviolet LED device, and further improving the light extraction efficiency of the deep ultraviolet LED device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional view of a deep ultraviolet LED device provided by an embodiment of the utility model along a second direction;

[0022] Figure 2 It is a schematic top view of part of the film layers in the deep ultraviolet LED device provided by the embodiment of the utility model;

[0023] Figure 3 It is a top view schematic diagram of an N-type contact electrode and a P-type contact electrode in a deep ultraviolet LED device provided by an embodiment of the utility model;

[0024] Figure 4A-4H It is a top view schematic diagram of each layer in the deep ultraviolet LED device provided by the embodiment of the utility model;

[0025] In the figure: 10-substrate; 200-slicing road; 201-groove group; 2011-first sub-groove; 2012-second sub-groove; 2013-third sub-groove; 20-MESA table layer; 21-intrinsic layer; 22-electron injection layer; 23-quantum well active layer; 24-electron blocking layer; 25-hole injection layer; 30-N-type contact electrode; 31-N-type contact sub-electrode; 40-P-type contact electrode; 50-first passivation layer; 51-first through hole; 52-second through hole; 60-connecting electrode; 70-second passivation layer; 72-first passivation opening; 71-second passivation opening; 80-N-type pad electrode; 90-P-type pad electrode. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] The technical solution of the present application is now described in conjunction with specific embodiments.

[0028] See also Figures 1 to 3 , Figure 1 is a cross-sectional view of a deep ultraviolet LED device provided by an embodiment of the utility model along a second direction; Figure 2 It is a schematic top view of part of the film layers in the deep ultraviolet LED device provided by the embodiment of the utility model; Figure 3 It is a top view schematic diagram of an N-type contact electrode and a P-type contact electrode in a deep ultraviolet LED device provided by an embodiment of the utility model.

[0029] Specifically, the deep ultraviolet LED device includes a plurality of epitaxial structures, each of which includes a substrate 10 and a MESA mesa layer 20 stacked in sequence along a growth direction, wherein the MESA mesa layer 20 is provided with a concave portion, and the concave portion does not completely penetrate the MESA mesa layer 20;

[0030] Among them, the deep ultraviolet LED device also includes an N-type contact electrode 30 and a P-type contact electrode 40, the N-type contact electrode 30 includes a plurality of N-type contact sub-electrodes 31 arranged at intervals from each other, and the plurality of N-type contact sub-electrodes 31 form an N-type electrode region, and the P-type contact electrode 40 is arranged on the top surface of the MESA table layer 20 and is located outside the N-type electrode region.

[0031] In the present invention, the substrate 10 is made of sapphire material; sapphire material has many advantages: first, the production technology of sapphire material is mature and the device quality is good; second, sapphire has good stability and can be used in high-temperature growth processes; finally, sapphire has high mechanical strength and is easy to handle and clean. Therefore, most processes generally use sapphire as the substrate 10.

[0032] In the present invention, the MESA mesa layer 20 includes an intrinsic layer 21, an electron injection layer 22, a quantum well active layer 23, an electron blocking layer 24 and a hole injection layer 25 stacked along the growth direction; wherein the MESA mesa layer 20 is provided with a recess, which does not completely penetrate the MESA mesa layer 20.

[0033] Specifically, the electron injection layer 22 includes a concave portion that penetrates a portion of the electron injection layer 22 ; the MESA mesa layer 20 forms a convex platform between two adjacent concave portions, and a quantum well active layer 23 , an electron blocking layer 24 and a hole injection layer 25 are sequentially formed on the convex platform.

[0034] In an embodiment of the utility model, the intrinsic layer 21 includes a low-temperature buffer layer arranged on the substrate 10 and an aluminum nitride layer arranged on the low-temperature buffer layer; wherein the material of the low-temperature buffer layer is aluminum nitride, and its growth temperature ranges between 400 degrees Celsius and 800 degrees Celsius, and its thickness ranges between 10nm and 50nm; the growth temperature range of the aluminum nitride layer is between 1200 degrees Celsius and 1400 degrees Celsius, and its thickness ranges between 500nm and 4000nm.

[0035] In an embodiment of the utility model, the material of the electron injection layer 22 is silicon-doped aluminum gallium nitride material, and the dopant is SiH4; wherein the composition range of aluminum element in the electron injection layer 22 is between 20% and 90%, the thickness range of the electron injection layer 22 is between 500nm and 4000nm, and the growth temperature range of the electron injection layer 22 is between 800 degrees Celsius and 1200 degrees Celsius.

[0036] In the embodiment of the utility model, the quantum well active layer 23 is disposed on the boss of the electron injection layer 22, and the growth temperature range of the quantum well active layer 23 is between 900 degrees Celsius and 1200 degrees Celsius.

[0037] Specifically, the quantum well active layer 23 includes at least one potential well layer and at least two potential barrier layers that are alternately arranged, and each potential well layer is inserted between two adjacent potential barrier layers; wherein the potential well layer and the potential barrier layer both include AlGaN material, and the total aluminum component content of each potential well layer is lower than the total aluminum component content of each barrier layer, so as to ensure that the carriers in the quantum well active layer 234 are confined in the potential well layer.

[0038] Furthermore, the material of the potential well layer is Al x1 Ga y1 N, the thickness of the potential well layer is 0.1nm~5nm, where 30%<x1<80%, and x1+y1=1; the material of the barrier layer is Al x2 Ga y2 N, the thickness of the barrier layer is 1nm~30nm, where 40%<x2<90%, and x2+y2=1.

[0039] Furthermore, the number of periods of the quantum well active layer 23 is greater than or equal to 1 and less than or equal to 20, and the number of periods is a positive integer.

[0040] In an embodiment of the utility model, the electron blocking layer 24 is a single-layer AlGaN structure, and the electron blocking layer 24 is a Mg-doped semiconductor material, which uses bismuth magnesium as a dopant; wherein the aluminum component content in the electron blocking layer 24 is greater than or equal to 50% and less than 100%, and the thickness of the electron blocking layer 24 ranges from 0.1nm to 200nm.

[0041] In an embodiment of the utility model, the hole injection layer 25 is arranged on the electron blocking layer 24, and the growth temperature range of the hole injection layer 25 is between 600 degrees Celsius and 1100 degrees Celsius; wherein, the material of the hole injection layer 25 is Mg-doped AlGaN material, the aluminum component content in the hole injection layer 25 is greater than or equal to 20% and less than or equal to 60%, and the thickness range of the hole injection layer 25 is between 1nm and 50nm.

[0042] Specifically, the hole injection layer 25 uses bis(cyclopentadienyl)magnesium as a dopant, and the doping concentration of the hole injection layer 256 is in the range of 1E18 cm -3 ~5E20cm -3 .

[0043] In the embodiment of the utility model, each epitaxial structure surface further includes a contact electrode assembly, which includes a P-type contact electrode 40 disposed on the hole injection layer 25 (on the boss) and an N-type contact electrode 30 disposed at the bottom surface of the concave portion of the electron injection layer 22;

[0044] Among them, the N-type contact electrode 30 includes a plurality of N-type contact sub-electrodes 31 spaced apart from each other, and each N-type contact sub-electrode 31 is correspondingly arranged on the bottom surface of the recess; a plurality of N-type contact sub-electrodes 31 form an N-type electrode region, and the P-type contact electrode 40 is arranged on the top surface of the MESA mesa layer 20 and is located outside the N-type electrode region.

[0045] Specifically, the material of the P-type contact electrode 40 includes but is not limited to at least one of Ni, Au, ITO, Rh, Al, Ti, Au, Pt and Pd, with a thickness of 10~70nm; the material of the N-type contact electrode 30 includes but is not limited to at least one of Cr, Al, Ti, Au, Ni, Pt, Rh, Pd and a high-conductivity N-type semiconductor material, with a thickness of 100~200nm.

[0046] Furthermore, the shortest distance between any two N-type contact sub-electrodes 31 is less than or equal to the current extension length of the deep ultraviolet LED device, and such a setting is conducive to current extension; wherein, according to the current extension model and current distribution theory established by X. Guo and E.F. Schubert, the current extension length formula of the deep ultraviolet LED device is as follows:

[0047] L S = ; (1)

[0048] Where, Ls is the current extension length of the deep ultraviolet LED device, c is the specific contact resistivity of the P-type semiconductor material, p is the resistivity of the P-type semiconductor material, T P is the thickness of the P-type contact electrode 40; T n is the thickness of the N-type contact electrode 30, n is the resistivity of N-type semiconductor material.

[0049] Specifically, according to formula (1), p , P c , T P , T n as well as n Under certain circumstances, the Ls value can be obtained, so that the distance between the N-type contact electrode 30 and the P-type contact electrode 40 can be reasonably designed according to the size of the Ls value, so that the current and heat distribution of the prepared deep ultraviolet LED device are uniform, thereby improving the photoelectric conversion efficiency.

[0050] See also Figures 1 to 4A The concave portion on the electron injection layer 22 includes a plurality of groove groups 201 arranged in a staggered manner along a first direction D1, and the groove group 201 includes a first sub-groove 2011, a second sub-groove 2012, and a third sub-groove 2013 arranged in sequence along a second direction D2, and the second direction D2 is perpendicular to the first direction D1;

[0051] The bottom surface shapes of the first sub-groove 2011 and the third sub-groove 2013 are circular, and the bottom surface shape of the second sub-groove 2012 is elliptical (in this embodiment, the ellipse is a combination of a rectangle and two semicircles).

[0052] In one embodiment, the spacing between two adjacent groove groups 201 is equal; in the same groove group 201, the first spacing between the second sub-groove 2012 and the first sub-groove 2011 is equal to the second spacing between the second sub-groove 2012 and the third sub-groove 2013.

[0053] In this embodiment, the bottom surface of the N-type contact sub-electrode 31 corresponding to the first sub-groove 2011 or the third sub-groove 2013 is circular, and the bottom surface of the N-type contact sub-electrode 31 corresponding to the second sub-groove 2012 is elliptical.

[0054] In the embodiment of the utility model, the deep ultraviolet LED device further includes a first passivation layer 50, which is deposited on the N-type contact electrode 30 and the P-type contact electrode 40 respectively, and the first passivation layer 50 is used to prevent the connection electrode 60 from contacting the P-type contact electrode 40 and causing a short circuit;

[0055] Specifically, the material of the first passivation layer 50 includes, but is not limited to, silicon oxide, silicon nitride, silicon nitride oxide, hafnium oxide, titanium oxide, magnesium fluoride, and the like.

[0056] In the embodiment of the utility model, the deep ultraviolet LED device further comprises a plurality of spaced connection electrodes 60, and the plurality of N-type contact sub-electrodes 31 corresponding to the same groove group 201 are electrically connected via one connection electrode 60;

[0057] The orthographic projection of the connecting electrode 60 on the substrate 10 is an ellipse-like shape (in the present embodiment, the ellipse-like shape is a combination of a rectangle and two semicircles).

[0058] Specifically, the material of the connection electrode 60 includes, but is not limited to, at least one of Cr, Pt, Pd, Al, Ti, Rh, Ni, Ag, and Au.

[0059] In an embodiment of the utility model, the deep ultraviolet LED device also includes a second passivation layer 70 located on the first passivation layer 50 and completely covering the connecting electrode 60. The second passivation layer 70 has first passivation openings 72 on multiple N-type contact sub-electrodes 31, and the first passivation layer 50 also has multiple second passivation openings 71 on the P-type contact electrode 40.

[0060] Specifically, the material of the second passivation layer 70 includes, but is not limited to, silicon oxide, silicon nitride, silicon nitride oxide, hafnium oxide, titanium oxide, magnesium fluoride, and the like.

[0061] In an embodiment of the utility model, the deep ultraviolet LED device also includes an N-type pad electrode 80 and a P-type pad electrode 90. The N-type pad electrode 80 is electrically connected to the N-type contact sub-electrode 31 through the first passivation opening 72, and the P-type pad electrode 90 is electrically connected to the P-type contact electrode 40 through the second passivation opening 71.

[0062] Preferably, the distance between the N-type pad electrode 80 and the P-type pad electrode 90 is 50-200 um.

[0063] Preferably, the N-type pad electrode 80 and the P-type pad electrode 90 both include at least one of Cr, Al, Ti, Au, Pt, Rh, Pd, Mg, Ag, Cu and Sn, and the total thickness is greater than 1.5 um.

[0064] See also Figure 3 , Figure 3 It is a top view schematic diagram of the N-type contact electrode 30 and the P-type contact electrode 40 in the deep ultraviolet LED device provided by the embodiment of the utility model; wherein, the edge line width spacing between the N-type contact sub-electrode 31 and the MESA table layer 20 is 3-10 um.

[0065] See also Figure 4A , Figure 4A 2 is a top view of the MESA mesa layer 20 in the deep ultraviolet LED device provided by the embodiment of the utility model; Figure 4A It can be seen that the MESA table layer 20 is provided with a concave portion, which includes a plurality of groove groups 201 arranged in a staggered manner along the first direction D1 (in this embodiment, each epitaxial structure has 5 groove groups 201), and each groove group 201 includes a first sub-groove 2011, a second sub-groove 2012 and a third sub-groove 2013 arranged in sequence and spaced apart from each other along the second direction D2, and the second direction D2 is perpendicular to the first direction D1;

[0066] The bottom surfaces of the first sub-groove 2011 and the third sub-groove 2013 are circular, and the bottom surface of the second sub-groove 2012 is elliptical.

[0067] Specifically, the staggered arrangement of two adjacent groove groups 201 can increase the distance between any two N-type contact sub-electrodes 31 in different groove groups 201, thereby increasing the current expansion channel and alleviating current congestion.

[0068] Preferably, the spacings between two adjacent groove groups 201 are equal; within the same groove group 201, the first spacing between the second sub-groove 2012 and the first sub-groove 2011 is equal to the second spacing between the second sub-groove 2012 and the third sub-groove 2013.

[0069] See also Figure 4B , Figure 4B2 is a top view schematic diagram of a scribe line 200 in a deep ultraviolet LED device provided by an embodiment of the present utility model; Figure 4B It can be seen that the MESA table layer 20 corresponds to Figure 4B The areas outside the filling area are etched to the substrate 10 to form a scribe line 200, so as to form a plurality of epitaxial structures of a deep ultraviolet LED; Figure 4B It can be seen that the bottom surfaces of the multiple epitaxial structures of the deep ultraviolet LED are square.

[0070] See also Figure 4C , Figure 4C is a top view schematic diagram of an N-type contact electrode 30 in a deep ultraviolet LED device provided by an embodiment of the utility model; wherein Figure 4C It can be known that the N-type contact electrode 30 includes a plurality of N-type contact sub-electrodes 31 , and each N-type contact sub-electrode 31 is correspondingly disposed at the bottom of the groove.

[0071] Specifically, when the N-type contact sub-electrode 31 is correspondingly arranged at the bottom of the first groove 101 or the third groove 103, the orthographic projection shape of the N-type contact sub-electrode 31 on the substrate 10 is circular; when the N-type contact sub-electrode 31 is correspondingly arranged at the bottom of the second groove 101, the orthographic projection shape of the N-type contact sub-electrode 31 on the substrate 10 is elliptical.

[0072] See also Figure 4D , Figure 4D is a top view schematic diagram of a P-type contact electrode 40 in a deep ultraviolet LED device provided by an embodiment of the utility model; wherein Figure 4D It can be seen that the P-type contact electrode 40 is completely disposed outside the concave portion of the MESA mesa layer 20 , and the edge line width interval between the P-type contact electrode 40 and the MESA mesa layer 20 is 3-15 um.

[0073] See also Figure 4E , Figure 4E is a top view schematic diagram of the first passivation layer 50 in the deep ultraviolet LED device provided by the embodiment of the utility model; wherein Figure 1 , Figure 2 as well as Figure 4E It can be known that the first passivation layer 50 opens a first through hole 51 and a second through hole 52 at positions corresponding to the recesses on the MESA mesa layer 20 , and the first through hole 51 and the second through hole 52 are prepared by a photolithography mask process.

[0074] Specifically, the bottom area of ​​the first through hole 51 is smaller than the bottom area of ​​the first sub-groove 2011 or the third sub-groove 2013, and the bottom area of ​​the second through hole 52 is smaller than the bottom area of ​​the second sub-groove 2012; the first through hole 51 and the second through hole 52 are used to electrically connect the connecting electrode 60 with multiple N-type contact electrodes 30 in the same groove group 201; wherein, the edge line width spacing between the first passivation layer 50 and the N-type contact sub-electrode 31 is 2~15um.

[0075] See also Figure 4F , Figure 4F is a top view schematic diagram of the connection electrode 60 in the deep ultraviolet LED device provided by the embodiment of the utility model; wherein Figure 1 , Figure 2 as well as Figure 4F It can be seen that multiple connecting electrodes 60 are arranged in a staggered manner along the second direction D2. This arrangement can increase the current expansion channel and alleviate current congestion. Among them, the line width of each connecting electrode 60 can be located within the first passivation layer 50 or outside the first passivation layer 50, but cannot exceed the edge line width of the MESA table layer 20.

[0076] See also Figure 4G , Figure 4G is a top view schematic diagram of the second passivation layer 70 in the deep ultraviolet LED device provided by the embodiment of the utility model; wherein Figure 1 , Figure 2 as well as Figure 4G It can be seen that the purpose of opening the first passivation opening 72 on the second passivation layer 70 is to electrically connect the N-type contact electrode 30 with the N-type pad electrode 80, and the purpose of opening the second passivation opening 71 is to electrically connect the P-type contact electrode 40 with the P-type pad electrode 90; at the same time, the second passivation layer 70 can also passivate and protect the position where the pad electrode material does not need to be deposited to avoid device leakage.

[0077] See also Figure 4H , Figure 4H A schematic top view of an N-type pad electrode 80 and a P-type pad electrode 90 in a deep ultraviolet LED device provided by an embodiment of the present utility model; Figure 1 as well as Figure 4H It can be seen that the distance between the N-type pad electrode 80 and the P-type pad electrode 90 is 50-200 um.

[0078] Compared with the prior art, the utility model designs a layout combining independent circles and long strips, which divides the traditional N-type semiconductor material into independent individuals and increases the current expansion channel. And through the current expansion model and current distribution theory established by X. Guo and EFSchubert, the current expansion length can be calculated. Through this current expansion length, the spacing between the N-type contact electrode 30 and the P-type contact electrode 40 can be reasonably designed, so that the current and heat distribution of the deep ultraviolet LED device prepared by it are uniform, thereby alleviating the current congestion effect, achieving uniform current and heat distribution, high photoelectric conversion efficiency, and long life.

[0079] Specifically, the utility model etches the concave portion of the MESA mesa layer 20 into a plurality of groove groups 201, and each groove group 201 has a first sub-groove 2011, a second sub-groove 2012 and a third sub-groove 2013 that are spaced apart along the second direction D2, and at the same time, three N-type contact sub-electrodes 31 are formed in each groove group 201. Compared with the two N-type contact sub-electrodes 31 formed in each groove group 201, the current expansion channel of the deep ultraviolet LED device in each groove group 201 is further increased, the current congestion effect of the deep ultraviolet LED device is alleviated, and the light extraction efficiency of the deep ultraviolet LED device is improved.

[0080] In summary, the utility model provides a deep ultraviolet LED device, including a substrate 10 and a MESA mesa layer 20 located on the substrate 10, the MESA mesa layer 20 is provided with a recess, and the recess does not completely penetrate the MESA mesa layer 20, wherein the deep ultraviolet LED device also includes an N-type contact electrode 30 and a P-type contact electrode 40, the N-type contact electrode 30 includes a plurality of N-type contact sub-electrodes 31 arranged at intervals from each other, each N-type contact sub-electrode 31 is correspondingly arranged on the bottom surface of the recess, and the plurality of N-type contact sub-electrodes 31 form an N-type electrode region, and the P-type contact electrode is arranged on the top surface of the MESA mesa layer 20 and is located outside the N-type electrode region; the utility model increases the current expansion channel of the deep ultraviolet LED device by dividing the traditional N-type contact electrode 30 into a plurality of independent N-type contact sub-electrodes 31, and arranges the P-type contact electrode 40 around the plurality of N-type contact sub-electrodes 31, thereby alleviating the current congestion effect of the deep ultraviolet LED device, and thereby improving the light extraction efficiency of the deep ultraviolet LED device.

[0081] It should be noted that the above embodiments all belong to the same utility model concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference can be made to the description in other embodiments.

[0082] The above embodiments only express the implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A deep ultraviolet LED device, characterized in that: A MESA mesa layer having a concave portion, wherein the concave portion does not completely penetrate the MESA mesa layer, and a plurality of N-type contact sub-electrodes spaced from each other are deposited on the bottom surface of the concave portion, wherein the plurality of N-type contact sub-electrodes form an N-type electrode region; Wherein, the deep ultraviolet LED device further includes a P-type contact electrode, and the P-type contact electrode is located on the top surface of the MESA mesa layer and outside the N-type electrode region.

2. The deep ultraviolet LED device according to claim 1, characterized in that: The shortest distance between any two of the N-type contact sub-electrodes is less than or equal to the current expansion length of the deep ultraviolet LED device.

3. The deep ultraviolet LED device according to claim 1, characterized in that: The concave portion includes a plurality of groove groups arranged alternately along a first direction, the groove groups include a first sub-groove, a second sub-groove and a third sub-groove arranged in sequence along a second direction, and the second direction is perpendicular to the first direction; The bottom surfaces of the first sub-groove and the third sub-groove are circular, and the bottom surface of the second sub-groove is elliptical.

4. The deep ultraviolet LED device according to claim 3, characterized in that: The spacing between two adjacent groove groups is equal; in the same groove group, the first spacing between the second sub-groove and the first sub-groove is equal to the second spacing between the second sub-groove and the third sub-groove.

5. The deep ultraviolet LED device according to claim 1, characterized in that: The edge line width spacing between the N-type contact sub-electrode and the MESA mesa layer is 3-10 um.

6. The deep ultraviolet LED device according to claim 1, characterized in that: The edge line width spacing between the P-type contact electrode and the MESA mesa layer is 3-15 um.

7. The deep ultraviolet LED device according to claim 3, characterized in that: The deep ultraviolet LED device further comprises a first passivation layer, which is deposited on the N-type contact electrode and the P-type contact electrode respectively, and the first passivation layer is provided with a first through hole and a second through hole at a position corresponding to the concave portion on the MESA mesa layer; Among them, the bottom area of ​​the first through hole is smaller than the bottom area of ​​the first sub-groove or the third sub-groove, and the bottom area of ​​the second through hole is smaller than the bottom area of ​​the second sub-groove; the edge line width spacing between the first passivation layer and the N-type contact sub-electrode is 2~15um.

8. The deep ultraviolet LED device according to claim 7, characterized in that: The deep ultraviolet LED device further comprises a plurality of spaced connection electrodes and a substrate, wherein the connection electrode is located on the first passivation layer, and the plurality of N-type contact sub-electrodes corresponding to the same groove group are electrically connected via one of the connection electrodes; The orthographic projection of the connecting electrode on the substrate is elliptical.

9. The deep ultraviolet LED device according to claim 7, characterized in that: The deep ultraviolet LED device also includes an N-type pad electrode and a P-type pad electrode. The N-type pad electrode is electrically connected to the N-type contact sub-electrode through a first passivation opening, and the P-type pad electrode is electrically connected to the P-type contact electrode through a second passivation opening.

10. The deep ultraviolet LED device according to claim 9, characterized in that: The distance between the N-type pad electrode and the P-type pad electrode is 50-200 um.

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