A micro-led structure containing a drive and a preparation method thereof

Abstract

The application discloses a driving-containing micro light emitting diode (Micro-LED) structure and a preparation method thereof. The structure comprises a gallium nitride (GaN) layer with a non-polar upward crystal face, a mask layer containing micropores, a GaN three-dimensional triangular island, and a high electron mobility transistor (HEMT) structure arranged on one side of the triangular island and a Micro-LED structure arranged on the other side of the triangular island. The GaN island with a three-dimensional structure is obtained by using selective epitaxy combined with lateral epitaxy. The GaN island naturally forms a left-right symmetrical structure due to its crystal properties. The HEMT and the Micro-LED structure are arranged on the two sides, respectively. The HEMT on one side can directly drive the Micro-LED on the other side. The problems of additional driving of the traditional Micro-LED are solved. The micropores are not bound to the current during the traditional selective epitaxy Micro-LED structure. In addition, the Micro-LED with an independent structure is grown on the inclined surface of the triangular island. The adverse effects caused by etching damage of the quantum well and the P-type layer in the traditional micro-processing technology can be avoided. The edge effect of each light emitting unit is effectively inhibited. The light emitting efficiency is improved. The light emitting units are arranged on the basis of close packing. The area of the epitaxial wafer can be effectively utilized to the maximum extent. The economic benefits are maximized.

Description

TECHNICAL FIELD

[0001] The application relates to a driving-containing Micro-LED structure and a preparation method thereof, and belongs to the fields of GaN-based HEMT, Micro-LED and the like. BACKGROUND

[0002] Micro-LED technology is a new display technology, which has significant advantages such as high brightness, wide color gamut and excellent contrast. However, the application of this technology also brings new challenges, one of which is the need for additional driving circuits. The core of Micro-LED is its array of tiny light-emitting diodes (LEDs), with each pixel composed of a single LED. This miniaturized structure allows each pixel to emit light independently, resulting in higher display precision and a wider color gamut.

[0003] However, this fine control requires each LED to be precisely driven and adjusted in brightness, thus requiring complex driving circuits to support. Specifically, the driving circuit of a Micro-LED screen needs to meet two main requirements. First, high-precision current control is required because the brightness of each LED needs to be very precisely adjusted to achieve the best display effect. Second, due to the very high pixel density of Micro-LED, the driving circuit must be able to handle a large amount of current and maintain efficient power distribution. These requirements make the design of the driving circuit complex and require optimization in terms of integration and heat dissipation design. In addition, the high-resolution and high-brightness characteristics of Micro-LED technology also impose higher performance requirements on the driving circuit. In order to maintain the consistency of the screen under different ambient light conditions, the driving circuit must be able to adjust the brightness of each LED in real time to meet various display requirements. This not only requires the driving circuit to have strong processing capability, but also needs to be optimized in terms of power consumption and heat management to ensure long-term stability and reliability. SUMMARY

[0004] The application aims to obtain a naturally formed left-right symmetrical GaN island structure by using selective epitaxy combined with lateral epitaxy, and to set HEMT and Micro-LED structures on the symmetrical two sides respectively, so that the HEMT on one side can directly drive the Micro-LED on the other side, solving the problem of additional driving required by traditional Micro-LED, and avoiding the constraint of micropores on current in the traditional selective epitaxy Micro-LED structure. As shown in the figure, when the structure is working, the carriers flow from the A electrode 107 of the left HEMT structure to the lower half 103 of the GaN three-dimensional triangular island and the AlGaN layer 102 on the right side, and then to the Micro-LED structure on the right side. Figure 3 x Ga 1-x ​The 2DEG formed between the N layers 105 diffuses to the N-doped strain regulation layer 109 of the right Micro-LED structure in the upper half of the N-doped GaN three-dimensional triangular island 104, and drives the Micro-LED. In addition, by using the three-dimensional independent island structure, the adverse effects caused by the etching damage of the quantum well and the P-type layer in the traditional micro-processing technology are avoided from the root, the edge effect of each light-emitting unit is effectively suppressed, and the light-emitting efficiency is improved; the light-emitting units are arranged on the basis of dense packing, the area of the epitaxial wafer can be effectively utilized to the maximum extent, and the economic benefit is maximized. At the same time, the semi-polar AlGaN / GaN heterojunction formed by the lattice symmetry has an acute angle between the interface and the polar axis, the 2DEG concentration is smaller than that of the traditional structure, and it is easier to control, and the island structure is beneficial to release the stress of the epitaxial material, improve the crystal quality of the prepared Micro-LED unit structure containing driving, and weaken the influence of defects and polarization on carriers. In order to improve the crystal quality, the size of the circumscribed circle diameter of the triangular mesa structure in the plane is specified. In order to reduce the influence of the polarization effect, Al x Ga 1-x N layer 105. In order to solve the problem of the quality of the GaN crystal grown by epitaxy due to the lack of a suitable substrate, an N-doped strain regulation layer is arranged, an Al x1 Ga 1-x1 N / GaN / Al x1 Ga 1-x1 N composite layer is arranged, high-quality quantum wells are obtained, and the overall Micro-LED light efficiency is improved. In order to achieve higher radiation recombination efficiency, an electron blocking layer with a wider band gap or a high P-doped hole injection layer is arranged.

[0005] In order to achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0006] On the one hand, the present application provides a Micro-LED structure containing driving, characterized in that: the structure comprises, from left to right and from bottom to top, a non-polar GaN layer 101 with an upward face, a mask layer 102 containing micropores, a GaN three-dimensional triangular island lower half 103, and an N-doped GaN three-dimensional triangular island upper half 104; wherein the GaN three-dimensional triangular island lower half 103 and the N-doped GaN three-dimensional triangular island upper half 104 form a whole triangular mesa structure S, which is obtained by upward epitaxial growth through the micropores of the mask layer 102, and contains two left and right symmetrical triangular inclined surfaces, a triangular side surface perpendicular to the bottom surface, and a triangular top surface parallel to the bottom surface and geometrically similar; the structure arranged on the left side comprises: an Al x Ga 1-xN layer 105, insulating dielectric layer 106, and A electrode 107 under the lower half of GaN stereoscopic triangular island 103, B electrode 108 on the insulating dielectric layer 106 and close to A electrode 107; wherein Al x Ga 1-x N layer 105 covers the left side slope of the lower half of GaN stereoscopic triangular island 103 and continues to extend upwards, covering the left side slope of the upper half of N doped GaN stereoscopic triangular island 104 not less than 30%; the structure arranged on the right side includes: N doped strain regulation layer 109 covering the right side of the entire triangular mesa structure S, quantum well layer 1010, carrier regulation layer 1011, P type In y Ga 1-y N layer 1012, C electrode 1013 with good ohmic contact. y Ga 1-y N layer 1012, C electrode 1013 with good ohmic contact.

[0007] Preferably, the mask layer 102 containing the micropore array is a 5-50 nm thick dielectric film plated on the non-polar GaN layer 101, wherein the dielectric film is one of SiO2, SiN or hBN, and the micropore array is etched from top to bottom by process technology, and the non-polar GaN layer 101 under the micropore is exposed; the diameter of the micropore is between 0.5-5 μm, and the micropores are arranged in a close-packed form with the center of any micropore being equal to the center distance of the adjacent six micropores, and can be adjusted according to actual needs.

[0008] Preferably, the upward crystal face of the non-polar GaN layer 101 and the triangular mesa structure S is simultaneously (11-20) face, at this time, the crystal faces of the left and right two slopes are simultaneously one of {1-101} or {1-102} crystal face family, since the crystal face family {1-101} or {1-102} is a lower potential face, a regular triangular island can be formed, and the layer structure above can be regularly and controllably grown; in addition, the upward crystal face of the non-polar GaN layer 101 and the triangular mesa structure S can also be simultaneously (1-100) face, at this time, the crystal faces of the left and right two slopes are simultaneously {20-21} crystal face family; in common, the triangular side surface perpendicular to the bottom surface is (000-1) face;

[0009] Preferably, when the micro-hole diameter of the mask layer 102 is not greater than 1.5 μm, the circumscribed circle diameter of the triangular mesa structure S in the plane is adjusted to be between 5-20 μm as needed, because when the micro-hole is small, regular islands are easy to form, and the size of the island can be controlled as needed; when the micro-hole diameter of the mask layer 102 is greater than 1.5 μm, the circumscribed circle diameter of the triangular mesa structure S in the plane is 3-4 times the micro-hole diameter, but the maximum is not more than 15 μm, because when the micro-hole is large, the island is easy to be irregular, and therefore the size of the island is limited. The island structure composed of the lower half of the GaN three-dimensional triangular island 103 and the upper half of the N-doped GaN three-dimensional triangular island 104 is beneficial to release the stress of the epitaxial material, improve the crystal quality of the prepared Micro-LED unit structure containing a driver, and weaken the influence of defects and polarization on the carriers.

[0010] Preferably, the upward crystal face of the GaN layer 101 is a (11-20) face, and the left and right two inclined faces are a {1-101} crystal face family, the Al x Ga 1-x N layer 105 has an Al component of 0.15 < x < 0.4 and a thickness of 2 / x ± 5 nm, because the angle between the (1-101) face and the (0002) face is about 61.9°, the polarization effect is low, and therefore a higher Al component or thickness is required; when the upward crystal face of the non-polar GaN layer 101 is a (11-20) face, and the left and right two inclined faces are a {1-102} crystal face family, the Al x Ga 1-x N layer 105 has an Al component of 0.1 < x < 0.3 and a thickness of 1.5 / x ± 5 nm, because the angle between the (1-102) face and the (0002) face is about 61.9°, the polarization effect is low, and therefore a higher Al component or thickness is required; when the upward crystal face of the non-polar GaN layer 101 is a (1-100) face, and the left and right two inclined faces are a {20-21} crystal face family, the Al x Ga 1-x N layer 105 has an Al component of 0.15 < x < 0.4 and a thickness of 3 / x ± 5 nm, because the angle between the (20-21) face and the (0002) face is about 75°, the polarization effect is very small, and therefore a higher Al component or a thicker thickness is required.

[0011] Preferably, the A electrode 107 is at the bottom of the left inclined face of the triangular mesa structure S and is in contact with the Al x Ga 1-x N layer 105, and is not in contact with the GaN three-dimensional triangular island lower half 103; the insulating dielectric layer 106 covers the Al x Ga 1-x N layer 105 from the side of the A electrode 107, and the coverage is > 30%; the B electrode 108 is in contact with the insulating dielectric layer 106 and is close to the side of the A electrode 107.

[0012] Preferably, the N-doped strain regulation layer 109 covers the right side slope of the entire triangular mesa structure S, and the structure is 1-3 periods of Al x1 Ga 1-x1 N / GaN / Al x1 Ga 1-x1 N composite layer, wherein the thickness of Al x1 Ga 1-x1 N is less than 3 nm, and x1 < 0.15. The introduction of lower component AlGaN can compensate for certain c-direction in-plane stress.

[0013] Preferably, when the light-emitting wavelength of the quantum well layer 1010 is red, green, and blue respectively, the number of quantum well pairs is 1-2 pairs, 2-4 pairs, and 3-5 pairs respectively; the layer structure of the quantum well is In x2 Ga 1-x2 N / GaN / Al x3 Ga 1-x3 N / GaN, wherein x3 = 2.5x2 ± 0.05, and the thickness of In x2 Ga 1-x2 N is 2-4 nm, and the total thickness of the two layers of GaN and Al x3 Ga 1-x3 N is not more than 6 nm. Among them, In x2 Ga 1-x2 N and GaN have a lattice mismatch value in the c direction of Δ1 = 0.09797x2; GaN and Al x3 Ga 1-x3 N have a lattice mismatch value in the c direction of Δ2 = -0.03915x3; by adjusting the mole components x2 and x3, the lattice mismatch value of Al x3 Ga 1-x3 N and In x2 Ga 1- x2 N in the c direction is equivalent to that of GaN (i.e. Δ1 = -Δ2), that is, x3 = 2.5x2 ± 0.05, so as to realize stress compensation between layers and obtain high-quality quantum wells and improve the overall Micro-LED light efficiency.

[0014] Preferably, the carrier regulation layer 1011 is one of an electron blocking layer or a hole injection layer; the electron blocking layer is an Al y1 Ga 1-y1 N / GaN superlattice, wherein the mole component y1 is between 0.1 and 0.6, and Al y1 Ga 1-y1The thickness of N is in negative correlation; the hole injection layer is P-doped Al y2 Ga 1-y2 N / In y3 Ga 1-y3 N / GaN superlattice, the Mg element doping concentration is 5*10 17 cm -3 ~1*10 19 cm -3 , and the hole concentration is not higher than 1*10 18 cm -3 . By setting the electron blocking layer with wider band gap or the hole injection layer with high P-doping, the carrier in the active region, i.e. the multi-quantum well, is limited, so that the overlap of the hole and electron wave functions in the multi-quantum well is increased, and higher radiation recombination efficiency is achieved.

[0015] Preferably, the P-type In y Ga 1-y N layer 1012 has a thickness of 50-200 nm, the molar component y is 0-0.15, y=0 is GaN, the Mg element doping concentration is 2*10 19 cm -3 ~5*10 19 cm -3 , and the hole concentration is not lower than 1*10 18 cm -3 ; wherein the P-type In y Ga 1-y N layer 107 has a thickness of 5-30 nm on the upper surface, the Mg element doping concentration is not less than 1*10 20 cm -3 , and the hole concentration is not lower than 5*10 18 cm -3 .

[0016] In another aspect, the application provides a preparation method of the Micro-LED structure with driving, which comprises, from left to right and from bottom to top, a non-polar GaN layer 101 with upward facets, a mask layer 102 containing micropores, a GaN triangular island lower half 103, and a N-doped GaN triangular island upper half 104; wherein the GaN triangular island lower half 103 and the N-doped GaN triangular island upper half 104 form an integral triangular platform structure S, which is obtained by upward epitaxial growth from the micropores of the mask layer 102 and contains two left-right symmetrical triangular inclined surfaces, a triangular side surface perpendicular to the bottom surface, and a triangular top surface parallel to the bottom surface and geometrically similar; the structure arranged on the left side comprises: an Al x Ga 1-xN layer 105, insulating dielectric layer 106, and A electrode 107 under the lower half of GaN pyramid triangle island 103, B electrode 108 on the insulating dielectric layer 106 and close to A electrode 107; wherein Al x Ga 1-x N layer 105 covers the left side slope of the lower half of GaN pyramid triangle island 103 and continues to extend upwards, covering not less than 30% of the left side slope of the upper half of N doped GaN pyramid triangle island 104; the structure arranged on the right side includes: N doped strain regulation layer 109 covering the right side of the entire triangle mesa structure S, quantum well layer 1010, carrier regulation layer 1011, P type In y Ga 1-y N layer 1012, C electrode 1013 with good ohmic contact to P type In y Ga 1-y N layer 1012. The preparation method of the Micro-LED structure containing the driver includes the following steps:

[0017] a) preparing a non-polar GaN template as a non-polar GaN layer 101, or epitaxially growing a non-polar GaN film on a sapphire, Si or SiC substrate as a non-polar GaN layer 101;

[0018] b) preparing a dielectric film on the non-polar GaN layer 101, using microprocessing technology to process a micro-hole structure on the dielectric layer to expose the underlying non-polar GaN layer 101;

[0019] c) using selective epitaxy growth technology to perform selective epitaxy using the above micro-holes, and then realizing lateral epitaxy by controlling the temperature,

[0020] V / III ratio, reaction chamber pressure and flow rate of carrier gas and reactant source during epitaxial growth to form a GaN pyramid triangle island;

[0021] d) during epitaxial growth, stopping the supply of Ga source, reducing the flow rate of N source, and performing in-situ annealing treatment on the GaN pyramid triangle island to decompose the GaN pyramid triangle island in-situ to form a lower half of GaN pyramid triangle island 103;

[0022] e) continuing epitaxial growth to grow an upper half of N doped GaN pyramid triangle island 104 on the lower half of GaN pyramid triangle island 103 to form an integral triangle mesa structure;

[0023] f) Using microfabrication techniques, a SiO2 or SiN dielectric layer is prepared on the left slope of the GaN 3D triangular island. Subsequently, using epitaxial growth techniques, an N-doped strain control layer 109, a quantum well layer 1010, a carrier control layer 1011, and a P-type In layer are sequentially formed on the right slope of the GaN 3D triangular island. y Ga 1-y Epitaxial growth of N-layer 1012;

[0024] g) Using reactive ion etching technology in a chlorine-free environment, SiO2 or...

[0025] The SiN dielectric layer was etched away, exposing the left slope of the GaN 3D triangular island;

[0026] h) Using microfabrication techniques, Al was sequentially fabricated on the left inclined surface of the GaN 3D triangular island. x Ga 1-x N layer 105 and insulating dielectric layer 106;

[0027] i) Using metal coating technology combined with microfabrication technology, electrode A 107, electrode B 108 and electrode C 1013 are fabricated at the corresponding positions to complete the fabrication of this driven Micro-LED structure.

[0028] Beneficial effects:

[0029] The structure provided by this invention is a GaN island with a three-dimensional structure obtained by selective epitaxy combined with lateral epitaxy. Due to its crystal properties, the GaN island naturally forms a symmetrical structure. HEMT and Micro-LED structures are respectively set on both sides. The HEMT on one side can directly drive the Micro-LED on the other side, solving the problem that traditional Micro-LEDs require additional driving. It also avoids the constraint of micro-holes for current in traditional selective epitaxy MicroLED structures.

[0030] When the micropore diameter of the mask layer 102 is not greater than 1.5 μm, the circumscribed circle diameter of the triangular mesa structure S in the plane is adjusted to be between 5-20 μm as needed, because when the micropore is small, regular islands are easy to form, and at this time, the size of the island can be controlled as needed; when the micropore diameter of the mask layer 102 is greater than 1.5 μm, the circumscribed circle diameter of the triangular mesa structure S in the plane is 3-4 times the micropore diameter, but is not greater than 15 μm, because when the micropore is large, the island is easy to be irregular, and therefore the size of the island is limited. And the island structure is beneficial to release the stress of the epitaxial material, improve the crystal quality of the prepared Micro-LED unit structure containing a drive, and weaken the influence of defects and polarization on carriers. When the upward crystal face of the GaN three-dimensional triangular island 103 is a (11-20) face, and the left and right two inclined faces are {1-101} crystal face families, because the angle between (1-101) and (0002) is 61.9°, the polarization effect is low, and therefore a higher Al component (0.15 < x < 0.4) or thickness (2 / x ± 5 nm) is needed; when the upward crystal face of the GaN three-dimensional triangular island 103 is a (11-20) face, and the left and right two inclined faces are {1-102} crystal face families, because the angle between (1-102) and (0002) is 43°, the polarization effect is acceptable, and therefore a lower Al component (0.1 < x < 0.3) or thickness (1.5 / x ± 5 nm) is needed; when the upward crystal face of the GaN three-dimensional triangular island 103 is a (1-100) face, and the left and right two inclined faces are {20-21} crystal face families, because the angle between (20-21) and (0002) is 75°, the polarization effect is very small, and therefore a higher Al component (0.15 < x < 0.4) or a thicker thickness (3 / x ± 5 nm) is needed. By adjusting the Al component and thickness of the GaN layer 104 with different components and thicknesses, the influence of the polarization effect can be reduced, the crystal quality can be improved, and the stability of the HEMT structure can be strengthened. x Ga 1-x N layer 104, the influence of the polarization effect can be reduced, the crystal quality can be improved, and the stability of the HEMT structure can be strengthened.

[0031] Meanwhile, the present application utilizes the semi-polar face AlGaN / GaN heterojunction formed by the lattice symmetry, the angle between the interface and the polar axis is an acute angle, and the 2DEG concentration generated is smaller than that of the traditional structure, and is easier to control. The Micro-LED with an independent structure is grown on the inclined face of the triangular island, which can avoid the adverse effects caused by the etching damage of the quantum well and the P-type layer in the traditional micro-processing technology, effectively suppress the edge effect of each light emitting unit, and improve the light emitting efficiency; the light emitting units are arranged on the basis of close packing, which can effectively utilize the area of the epitaxial wafer to the greatest extent, and maximize the economic benefits.

[0032] In order to alleviate the In x Ga 1-xThe N quantum well has a series of adverse effects caused by a large lattice mismatch with GaN, such as defects caused by stress release. The present application sets a strain regulation layer and a specially designed quantum well structure before growing the quantum well, and introduces an AlGaN layer with a specific mole fraction to generate a strain opposite to that of InGaN, so as to offset the strain of InGaN. The principle is as follows: first, according to the formula

[0033]

[0034] The lattice mismatch value is calculated, where Δ is the lattice mismatch value, c GaN is the c-axis lattice constant of GaN, which is 5.185 angstroms, c n represents the c-axis lattice constant of Al x1 Ga 1-x1 N and In x Ga 1-x N. Wherein c n The calculation formula is:

[0035] c n = b x c AlN或InN + (1-b) c GaN

[0036] Wherein b is x2 or x3, c AlN或InN is the c-axis lattice constant of AlN or InN, which is 4.982 angstroms and 5.693 angstroms respectively. By substituting the corresponding values, the lattice mismatch value of In x2 Ga 1-x2 N and GaN in the c direction is Δ1=0.09797x2; the lattice mismatch value of Al x3 Ga 1-x3 N and GaN in the c direction is Δ2=-0.03915x3. By adjusting the mole fractions x2 and x3, the lattice mismatch value of In x2 Ga 1-x2 N and Al x3 Ga 1-x3 N in the c direction with GaN is equivalent (i.e. Δ1=-Δ2), that is, x3=2.5x2±0.05, at this time, AlGaN will generate a strain opposite to that of InGaN and close in value, so as to offset the strain of InGaN, inhibit the defects caused by excessive strain of InGaN, and thus obtain high-quality quantum wells and improve the overall Micro-LED light efficiency.

[0037] The electron blocking layer with a wider band gap or the high-P-doped hole injection layer is set, so as to limit the carriers in the active region, i.e. the multi-quantum well, so that the overlap of the hole and electron wave functions in the multi-quantum well is increased, a higher radiation recombination efficiency is realized, and the problem of decrease of internal quantum efficiency caused by increase of injection current density is further solved. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A cross-sectional view of a Micro-LED structure with driving provided by the present application.

[0039] Figure 2 A top view of a Micro-LED structure with driving provided by the present application.

[0040] Figure 3 A carrier flow direction diagram of a Micro-LED structure with driving provided by the present application.

[0041] Wherein, 101 is a GaN layer with a non-polar upward crystal surface; 102 is a mask layer containing micropores; 103 is the lower half of a GaN three-dimensional triangular island; 104 is the upper half of an N-doped GaN three-dimensional triangular island; 105 is an Al x Ga 1-x N layer; 106 is an insulating medium layer, 107 is an A electrode; 108 is a B electrode; 109 is an N-doped strain regulation layer; 1010 is a quantum well layer; 1011 is a carrier regulation layer; 1012 is a P-type In y Ga 1-y N layer; 1013 is a C electrode. DETAILED DESCRIPTION

[0042] The present application will be further described below in conjunction with the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0043] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0044] Example 1

[0045] A cross-sectional view of a Micro-LED structure with driving provided by the present application according to Example 1 is shown in Figure 1 A top view of a Micro-LED structure with driving provided by the present application according to Example 1 is shown in Figure 2As shown, the driving-containing Micro-LED structure includes, from left to right and from bottom to top, a non-polar GaN layer 101 with an upward crystal face of (11-20) face, a mask layer 102 containing micropores, a GaN triangular island lower half 103, and an N-doped GaN triangular island upper half 104; wherein the GaN triangular island lower half 103 and the N-doped GaN triangular island upper half 104 form an integral triangular mesa structure S, which is obtained by upward epitaxial growth in the micropores of the mask layer 102 and contains two left-right symmetrical triangular inclined surfaces, a triangular side surface perpendicular to the bottom surface, and a triangular top surface parallel to the bottom surface and geometrically similar; the structure arranged on the left side includes: an Al x Ga 1-x N layer 105 with an Al composition x = 0.15, an insulating dielectric layer 106, and an A electrode 107 below the GaN triangular island lower half 103 and a B electrode 108 on the insulating dielectric layer 106 and close to the A electrode 107; wherein the Al x Ga 1-x N layer 105 covers the left side inclined surface of the GaN triangular island lower half 103 and continues to extend upward, covering 50% of the left side inclined surface of the N-doped GaN triangular island upper half 104; the structure arranged on the right side includes: an N-doped strain regulation layer 109 covering the right side of the entire triangular mesa structure S, a quantum well layer 1010, a carrier regulation layer 1011, a P-type In y Ga 1-y N layer 1012, and a C electrode 1013 with good ohmic contact to the P-type In y Ga 1-y N layer 1012.

[0046] The upward crystal face of the non-polar GaN layer 101 and the triangular mesa structure S is simultaneously a (11-20) face, wherein the circumscribed circle diameter of the triangular mesa structure S in the plane is 10 μm.

[0047] A 30-nm-thick SiO2 dielectric film is plated on the N-type GaN layer 101 as a mask layer 102, and a micropore array is etched from top to bottom by process technology, with the lower GaN layer 101 exposed in the micropores. The micropore diameter of the mask layer 102 is 1 μm.

[0048] The Al x Ga 1-x N layer 105 covers the left side of the triangular mesa structure S, wherein the Al composition x = 0.15 and the thickness is 12 nm.

[0049] The A electrode 107 is at the bottom of the triangular mesa structure S, and the insulating dielectric layer 106 covers the Al x Ga 1-xN layer 105, coverage rate is 50%, B electrode 108 is in contact with insulating medium layer 106, and is close to one side of A electrode 107.

[0050] N doped strain regulation layer 109 covers the right side slope of the whole triangular mesa structure S, and the structure is 3 periods of Al x1 Ga 1-x1 N / GaN / Al x1 Ga 1-x1 N composite layer, wherein the thickness of Al x1 Ga 1-x1 N is 2nm, and the molar component x1 is 0.1.

[0051] When the quantum well layer 1010 emits red, green and blue light respectively, the number of quantum well pairs is 2 pairs, 3 pairs and 2 pairs respectively; the layer structure of the quantum well is In x2 Ga 1-x2 N / GaN / Al x3 Ga 1-x3 N / GaN, wherein the molar components x2 and x3 are 0.2 and 0.5 respectively, and the thickness of In x2 Ga 1-x2 N is 2nm, and the total thickness of the two layers of GaN and Al x3 Ga 1-x3 N is 5nm.

[0052] The carrier regulation layer 1011 is an electron blocking layer, wherein the electron blocking layer is a 4-period Al y1 Ga 1-y1 N / GaN superlattice, and the molar component y1 is 0.5.

[0053] The P-type In y Ga 1-y N layer 1012 has a thickness of 100nm, a molar component y of 0.1, and a Mg element doping concentration of 4*10 19 cm -3 , and a hole concentration of 2*10 18 cm -3 -2; wherein the P-type In y Ga 1-y N layer 107 has a Mg element doping concentration of 2*10 20 cm -3 -2 in a 30nm-thick region on the upper surface, and a hole concentration of 6*10 18 cm -3 -2.

[0054] The preparation method of the Micro-LED structure provided by the embodiment 1 of the application comprises the following steps:

[0055] a) prepare a non-polar (11-20) GaN template as a non-polar GaN layer 101, the upward crystal surface of the non-polar GaN layer 101 and the triangular mesa structure S are both (11-20) surfaces, and the left and right inclined surfaces are both {1-102} crystal surface families;

[0056] b) prepare a dielectric thin film on the non-polar GaN layer 101, and use microprocessing technology to process a micropore structure on the dielectric layer, with a micropore diameter of 1 μm, to expose the underlying non-polar GaN layer 101;

[0057] c) use selective epitaxy growth technology to perform selective epitaxy through the micropore, and then realize lateral epitaxy by controlling the temperature, V / III ratio, reaction chamber pressure, and flow rate of the carrier gas and reactant source during epitaxial growth, to form a GaN three-dimensional triangular island; d) during epitaxial growth, stop supplying the Ga source, reduce the flow rate of the N source, and perform in-situ annealing treatment on the GaN three-dimensional triangular island, so that the GaN three-dimensional triangular island is decomposed in-situ to form a lower half 103 of the GaN three-dimensional triangular island; e) continue epitaxial growth to grow an N-doped GaN three-dimensional triangular island upper half 104 on the lower half 103 of the GaN three-dimensional triangular island, to form an integral triangular mesa structure S, and the in-plane circumscribed circle diameter of the structure is 10 nm; f) combine microprocessing technology to prepare a SiO2 dielectric layer on the left inclined surface of the GaN three-dimensional triangular island, and then use epitaxial growth technology to sequentially complete epitaxial growth of an N-doped strain regulation layer 109, a sequentially covered quantum well layer 1010, a carrier regulation layer 1011, and a P-type In y Ga 1-y N layer 1012 on the right inclined surface of the GaN three-dimensional triangular island;

[0058] g) use reactive ion etching technology to etch away the SiO2 dielectric layer prepared on the left inclined surface of the GaN three-dimensional triangular island in a chlorine-free environment, to expose the left inclined surface of the GaN three-dimensional triangular island;

[0059] h) use microprocessing technology to sequentially prepare an Al x Ga 1-x N layer 105 with an Al composition x = 0.15 and a thickness of 12 nm on the left inclined surface of the GaN three-dimensional triangular island, and cover the Al x Ga 1-x N layer 105 with an insulation dielectric layer 106 with a coverage rate of 50% from the A electrode 107 side;

[0060] i) use metal plating technology combined with microprocessing technology to prepare the A electrode 107, the B electrode 108, and the C electrode 1013 at the corresponding positions, to complete the preparation of the Micro-LED structure containing the driver.

Claims

1. A drive-in Micro-LED structure, characterized in that: The structure comprises, from left to right and from bottom to top, an N-type GaN layer with upward crystal face being a non-polar face, a mask layer containing a micro-pore array, a GaN stereoscopic triangular island lower half part, and an N-doped GaN stereoscopic triangular island upper half part; wherein the GaN stereoscopic triangular island lower half part and the N-doped GaN stereoscopic triangular island upper half part form an integral triangular mesa structure S, which is obtained by upward epitaxial growth through the micro-pore of the mask layer, and contains, except for the bottom, two left-right symmetrical triangular inclined surfaces, a triangular side surface perpendicular to the bottom surface, and a triangular top surface parallel to the bottom surface and geometrically similar to the triangular side surface; the structure arranged on the left side comprises: an Al x Ga 1-x N layer with Al component 0.1 < x < 0.4, an insulating dielectric layer, and an A electrode below the GaN stereoscopic triangular island lower half part and a B electrode on the insulating dielectric layer and close to the A electrode; wherein the Al x Ga 1-x N layer covers the left side inclined surface of the GaN stereoscopic triangular island lower half part and continues to extend upward, and covers no less than 30% of the left side inclined surface of the N-doped GaN stereoscopic triangular island upper half part; the structure arranged on the right side comprises: an N-doped strain regulation layer covering the right side of the entire triangular mesa structure S, a quantum well layer, a carrier regulation layer, a P-type In y Ga 1-y N layer, and a C electrode in ohmic contact with the P-type In y Ga 1-y N layer.

2. The drive-in Micro-LED structure of claim 1, wherein: The mask layer containing the micropore array is a micropore array etched from top to bottom by a process after a 5-50 nm thick medium film of one of SiO2, SiN or hBN is plated on the non-polar N-type GaN layer, and the non-polar N-type GaN layer is exposed in the micropores; wherein the diameter of the micropore is between 0.5-5 μm, and the micropores are arranged in a close-packed form with the centers of the micropores being equal to the distance between the centers of the six adjacent micropores.

3. The drive-in Micro-LED structure of claim 1, wherein: The upward crystal face of the non-polar N-type GaN layer and the triangular mesa structure S is simultaneously a (11-20) face, and the crystal faces of the left and right two inclined faces are simultaneously one of the {1-101} or {1-102} crystal face families; alternatively, the upward crystal face of the non-polar N-type GaN layer and the triangular mesa structure S is simultaneously a (1-100) face, and the crystal faces of the left and right two inclined faces are simultaneously a {20-21} crystal face family; the triangular side face perpendicular to the bottom face is a (000-1) face; when the diameter of the micropore of the mask layer is not greater than 1.5 μm, the circumscribed circle diameter of the triangular mesa structure S in the plane is between 5-20 μm; when the diameter of the micropore of the mask layer is greater than 1.5 μm, the circumscribed circle diameter of the triangular mesa structure S in the plane is 3-4 times the diameter of the micropore, but is not greater than 15 μm.

4. The drive-in Micro-LED structure of claim 1, wherein: When the upward crystal face of the non-polar N-type GaN layer is (11-20) face, and the left and right two inclined faces are {1-101} crystal face family, the Al x Ga 1-x N layer has an Al component of 0.15 < x < 0.4, and a thickness of 2 / x ± 5 nm; when the upward crystal face of the non-polar N-type GaN layer is (11-20) face, and the left and right two inclined faces are {1-102}, the Al x Ga 1-x N layer has an Al component of 0.1 < x < 0.3, and a thickness of 1.5 / x ± 5 nm; when the upward crystal face of the non-polar N-type GaN layer is (1-100) face, and the left and right two inclined faces are {20-21} crystal face family, the Al x Ga 1-x N layer has an Al component of 0.15 < x < 0.4, and a thickness of 3 / x ± 5 nm.

5. The driving-included Micro-LED structure of claim 1, wherein: A electrode is at the bottom of the left side inclined surface of the triangular mesa structure S, and contacts with Al x Ga 1-x N layer, and does not contact with the triangular mesa structure S; the insulating medium layer covers the Al x Ga 1-x N layer from the side of the A electrode, and the coverage is >30%; the B electrode contacts with the insulating medium layer, and is close to the side of the A electrode.

6. The drive-in Micro-LED structure of claim 1, wherein: The N-doped strain regulating layer covers the right side slope of the triangular mesa structure S, and the structure is 1-3 periods of Al x1 Ga 1-x1 N / GaN / Al x1 Ga 1-x1 N composite layer, wherein the thickness of Al x1 Ga 1-x1 N is less than 3 nm, and x1<0.

15.

7. The drive-in Micro-LED structure of claim 1, wherein: When the quantum well layer emits red, green and blue light respectively, the number of quantum well pairs is 1-2 pairs, 2-4 pairs and 3-5 pairs respectively; the layer structure of the quantum well is In x2 Ga 1-x2 N / GaN / Al x3 Ga 1-x3 N / GaN, wherein x3=2.5x2±0.05, and In x2 Ga 1-x2 N, the thickness of the two layers of GaN and Al x3 Ga 1-x3 N is not more than 6 nm.

8. The drive-in Micro-LED structure of claim 1, wherein: The carrier modulation layer is one of an electron blocking layer and a hole injection layer; the electron blocking layer is an Al y1 Ga 1-y1 N / GaN superlattice with a molar composition y1 between 0.1 and 0.6, and a thickness of Al y1 Ga 1-y1 N that is negatively correlated with the thickness of Al y2 Ga 1-y2 N / In y3 Ga 1-y3 N / GaN superlattice with a Mg element doping concentration between 5×10 17 cm -3 ~1×10 19 cm -3 , and a hole concentration not higher than 1×10 18 cm -3 .

9. The drive-in Micro-LED structure of claim 1, wherein: P-type In y Ga 1-y N layer has a thickness of 50-200 nm, a molar composition y of 0-0.15, and when y=0, it is GaN; the Mg element doping concentration is 2×10 19 cm -3 -5×10 19 cm -3 , and the hole concentration is not less than 1×10 18 cm -3 ; wherein the P-type In y Ga 1-y N layer has a thickness of 5-30 nm on the upper surface, the Mg element doping concentration is not less than 1×10 20 cm -3 , and the hole concentration is not less than 5×10 18 cm -3 .

10. A preparation method of the Micro-LED structure according to claim 1, comprising the following steps: a) preparing a non-polar GaN template as the non-polar N-type GaN layer, or epitaxially growing a non-polar N-type GaN film on a sapphire, Si or SiC substrate as the non-polar N-type GaN layer; b) preparing a medium film on the non-polar N-type GaN layer, and using a microprocessing process to process a micropore structure on the medium layer to expose the underlying non-polar N-type GaN layer; c) using a selective epitaxial growth technique to perform selective epitaxy using the micropore, and then performing lateral epitaxy by controlling the temperature, V / III ratio, reaction chamber pressure and flow rate of the carrier gas and reactant source to form a GaN three-dimensional triangular island; d) during epitaxial growth, stopping the supply of Ga source, reducing the flow rate of N source, and performing in-situ annealing treatment on the GaN three-dimensional triangular island to decompose the GaN three-dimensional triangular island in-situ to form a lower half of the GaN three-dimensional triangular island; e) continuing epitaxial growth to grow an N-doped GaN upper half on the lower half of the GaN three-dimensional triangular island to form an integral triangular mesa structure; f) in combination with micro-processing technology, a SiO2 or SiN dielectric layer is prepared on the left side slope of the GaN stereoscopic triangular island, and then using epitaxial growth technology, on the right side slope of the GaN stereoscopic triangular island, epitaxial growth of N-doped strain regulation layer, sequentially covered quantum well layer, carrier regulation layer and P-type In y Ga 1-y N layer is completed in sequence; g) using a reactive ion etching technique to etch away the SiO2 or SiN medium layer prepared on the left inclined face of the GaN three-dimensional triangular island in a chlorine-free environment to expose the left inclined face of the GaN three-dimensional triangular island; h) using microfabrication technology, successively preparing Al x Ga 1-x N layer and insulating medium layer on the left side slope of the GaN stereoscopic triangular island. i) using a metal plating film technique in combination with a microprocessing technique to prepare A, B and C electrodes at the corresponding positions to complete the preparation of the Micro-LED structure containing the driver.

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