CN-121038460-B - Deep ultraviolet LED device with photoinduced hole compensation structure and preparation method thereof

CN121038460BCN 121038460 BCN121038460 BCN 121038460BCN-121038460-B

Abstract

The invention discloses a deep ultraviolet LED device with a photoinduced hole compensation structure and a preparation method thereof, wherein the LED device sequentially comprises the following components from bottom to top: the electron transport layer is partially exposed, the upper surface of the exposed part is covered with the n-type ohmic electrode, at least one groove is etched in the hole injection layer, the n-type light absorption layer is deposited in the groove, and the p-type ohmic electrode is covered on the hole injection layer and the n-type light absorption layer. The invention is beneficial to the vertical/quasi-vertical injection of holes into the active region, improves the concentration of holes in the active region, can horizontally inject holes into a metal-semiconductor interface, improves the concentration of holes on the surface of a p-type semiconductor layer, reduces interface potential barrier, effectively inhibits phonon generation in the photon-hole conversion process, reduces the junction temperature of a device and improves the thermal stability of the device.

Inventors

ZHANG ZIHUI
CHU CHUNSHUANG
TIAN KANGKAI
JIANG YAO
HUANG FUPING

Assignees

广东工业大学

Dates

Publication Date: 20260512
Application Date: 20250703

Claims (10)

1. The deep ultraviolet LED device with the photoinduced hole compensation structure is characterized by sequentially comprising a substrate, a buffer layer, an electron transmission layer, an active region, an electron blocking layer, a hole injection layer, an n-type light absorption layer, an insulating layer, a p-type ohmic electrode, an n-type ohmic electrode and a reflector electrode from bottom to top; The electron transmission layer is partially exposed, the upper surface of the electron transmission layer of the exposed part is covered with an n-type ohmic electrode, at least one groove is etched in the hole injection layer, an n-type light absorption layer is deposited in the groove, and p-type ohmic electrodes are covered on the hole injection layer and the n-type light absorption layer.
2. The deep ultraviolet LED device with photohole compensation structure of claim 1, wherein the overall pattern of the device comprises triangles, circles, rectangles and rings.
3. The deep ultraviolet LED device with the photo-induced hole compensation structure according to claim 1, wherein the etching depth of each groove is 10 nm-100 nm, the etching width is 5 μm-100 μm, and the area of the groove part accounts for 10% -80% of the total area of the hole injection layer and the ohmic contact layer.
4. The deep ultraviolet LED device with the photohole compensation structure according to claim 1, wherein the substrate is made of at least any one of sapphire, siC, si, alN, gaN or quartz glass, and the substrate is divided into a polar surface substrate, a semi-polar surface substrate or a nonpolar surface substrate along the difference of epitaxial growth directions.
5. The deep ultraviolet LED device with the photo-induced hole compensation structure according to claim 1, wherein the buffer layer is made of AlGaN and AlN, and the thickness of the buffer layer is 500 nm-2 μm.
6. The deep ultraviolet LED device with the photo-induced hole compensation structure according to claim 1, wherein the electron transport layer is made of Al x1 Ga 1-x1 N, wherein x1 is more than or equal to 0 and less than or equal to 1, x1 is more than or equal to 0 and less than or equal to 1-x1 is more than or equal to 1, the thickness is1 μm to 4 μm, and the exposed part of the electron transport layer accounts for 5% -80% of the whole electron transport layer.
7. The deep ultraviolet LED device with the photo-induced hole compensation structure according to claim 1, wherein the active region comprises a plurality of layers of quantum barriers and quantum wells, the quantum barriers are made of Al x2 Ga 1-x2 N, x2 is more than or equal to 0 and less than or equal to 1-x2 is more than or equal to 1, the quantum wells are made of Al x3 Ga 1-x3 N, x3 is more than or equal to 0 and less than or equal to 1, x3 is more than or equal to 1 and x3 is more than or equal to 1, and the thickness of the active region is 10 nm-300 nm.
8. The deep ultraviolet LED device with the photo-induced hole compensation structure according to claim 1, wherein the electron blocking layer is made of Al x4 Ga 1-x4 N, wherein x4 is more than or equal to 0 and less than or equal to 1, x4 is more than or equal to 0 and less than or equal to 1-x4 is more than or equal to 1, x2 is more than or equal to x4, and the thickness is10 nm-40 nm; The hole injection layer is made of Al x5 Ga 1-x5 N, wherein x5 is more than or equal to 0 and less than or equal to 1, x5 is more than or equal to 0 and less than or equal to 1-x5 is more than or equal to 1, and the thickness is 10 nm-100 nm; The n-type light absorption layer is made of BN, ga 2 O 3 , znO, gaN or AlGaN, and the thickness of the n-type light absorption layer is 10 nm-100 nm; The insulating layer is made of SiO 2 、HfO 2 or Al 2 O 3 , and the thickness of the insulating layer is 20 nm-1 mu m.
9. The deep ultraviolet LED device with the photohole compensation structure according to claim 1, wherein the p-type ohmic electrode is made of Ni/Au, ni/Al, cr/Au or Pt/Au, the n-type ohmic electrode is made of Cr/Al, al/Au, cr/Au or Ti/Al/Ti/Au, and the reflector electrode is made of Al/Ti/Au, ti/Al/Ti/Au.
10. A method for preparing a deep ultraviolet LED device with a photo-induced hole compensation structure, for preparing a deep ultraviolet LED device with a photo-induced hole compensation structure according to claims 1-9, characterized in that the method comprises the steps of: s1, firstly, baking a substrate in an MOCVD reaction furnace at 950-1350 ℃ to remove foreign matters on the surface of the substrate, and then respectively growing a buffer layer, an electron transport layer, an active region, an electron blocking layer, a hole injection layer and an ohmic contact layer; s2, exposing the product obtained in the step S1 to an electron transport layer through photoetching and deep etching, and etching to form a table top; S3, etching grooves in the hole injection layer and the ohmic contact layer through photoetching and dry etching processes on the mesa obtained in the step S2; s4, on the basis of S3, growing an n-type light absorption layer material in the groove by using MOCVD or magnetron sputtering technology; s5, manufacturing an n-type ohmic electrode and a p-type ohmic electrode of the LED by utilizing photoetching and electron beam evaporation technology on the basis of S4; s6, growing an insulating layer by utilizing PECVD or ALD technology on the basis of S5, wherein the thickness of the insulating layer is 20 nm-1 mu m; s7, removing the insulating layers covering the n-type ohmic electrode and the p-type ohmic electrode by utilizing photoetching and wet etching technologies on the basis of S6; s8, on the basis of S7, manufacturing the reflecting mirror electrode of the LED by utilizing photoetching and electron beam evaporation technology.

Description

Deep ultraviolet LED device with photoinduced hole compensation structure and preparation method thereof Technical Field The invention relates to the field of semiconductor photoelectricity, in particular to a deep ultraviolet LED device with a photoinduced hole compensation structure and a preparation method thereof. Background Deep ultraviolet LEDs are solid state light sources with emission wavelengths in the range of 200-280 nm. Compared with the traditional mercury lamp, the deep ultraviolet LED has the advantages of small volume, long service life, low energy consumption, environmental protection, no mercury and the like, so the deep ultraviolet LED has wide application prospect in the fields of disinfection, environmental monitoring, ultraviolet communication and the like, but the luminous efficiency and the electro-optical conversion efficiency of the deep ultraviolet LED at the present stage cannot meet the actual application requirements. The problems of low luminous efficiency and low electro-optic conversion efficiency of the deep ultraviolet LED mainly come from factors such as low carrier injection efficiency, serious photon self-absorption effect, serious hole depletion of a metal-semiconductor interface and the like. In order to solve the problem CN 113594311A, a hole compensation layer of a P-type semiconductor layer is designed, so that the absorption of the inner structure of the deep ultraviolet LED chip to deep ultraviolet light is reduced while the P-type semiconductor layer obtains higher hole concentration. The CN 112885933A designs patterned bulges or pits on the surface of the N-type semiconductor transmission layer, so that on one hand, the contact area between an N electrode and an N-AlGaN layer is increased, the contact resistance is reduced, on the other hand, the scattering effect of light on the surface of the N-AlGaN layer is improved, the optical waveguide effect of the N-AlGaN layer is broken, the light emitting efficiency and the light extraction efficiency at the bottom of the device are further improved, and finally the photoelectric conversion efficiency of the device is improved. However, the light extraction efficiency of the current deep ultraviolet LED is difficult to further improve, and in particular, more than 90% of photons in the small-sized and short-band deep ultraviolet LED cannot escape, and are finally absorbed and converted into phonons by the material. Disclosure of Invention The invention aims to solve the problems of low luminous efficiency and low electro-optic conversion efficiency caused by serious photon self-absorption and serious hole exhaustion at a metal-semiconductor interface of the deep ultraviolet LED in the prior art. In order to achieve the aim, the first aspect of the invention provides a deep ultraviolet LED device with a photoinduced hole compensation structure, which sequentially comprises a substrate, a buffer layer, an electron transmission layer, an active region, an electron blocking layer, a hole injection layer, an n-type light absorption layer, an insulating layer, a p-type ohmic electrode, an n-type ohmic electrode and a reflecting mirror electrode from bottom to top; The electron transmission layer is partially exposed, the upper surface of the electron transmission layer of the exposed part is covered with an n-type ohmic electrode, at least one groove is etched in the hole injection layer, an n-type light absorption layer is deposited in the groove, and p-type ohmic electrodes are covered on the hole injection layer and the n-type light absorption layer. Preferably, the overall pattern of the device includes triangles, circles, rectangles and circles. Preferably, the etching depth of each groove is 10 nm-100 nm, the etching width is 5-100 μm, and the area of the groove part accounts for 10% -80% of the total area of the hole injection layer and the ohmic contact layer. Preferably, the substrate is made of at least one of sapphire, siC, si, alN, gaN or quartz glass, and the substrate is divided into a polar surface substrate, a semi-polar surface substrate or a nonpolar surface substrate along the difference of the epitaxial growth direction. Preferably, the buffer layer is made of AlGaN and AlN, and the thickness of the buffer layer is 500 nm-2 mu m. Preferably, the electron transport layer is made of Al x1Ga1-x1 N, wherein x1 is more than or equal to 0 and less than or equal to 1, x1 is more than or equal to 0 and less than or equal to 1-x1 is more than or equal to 1, the thickness is 1 mu m-4 mu m, and the exposed part of the electron transport layer accounts for 5% -80% of the whole electron transport layer. Preferably, the active region comprises a plurality of layers of quantum barriers and quantum wells, the quantum barriers are made of Al x2Ga1-x2 N, x2 is more than or equal to 0 and less than or equal to 1-x2 is more than or equal to 1, the quantum wells are made of Al x3Ga1-x3 N, x3 is more than or equal to 0 and