CN113036009B - A thin film vertically integrated unit diode chip - Google Patents

Abstract

The invention provides a thin-film vertically integrated unit diode chip, comprising: a protective metal layer, a mirror, a second conductivity type layer, a second conductivity type electrode, a quantum well active region, a first conductivity type layer, an insulating medium layer, a A conductivity type electrode, and n diode mesa structures and trench structures are formed on the side away from the first conductivity type electrode, and the trench structures are located between the diode units; the adjacent diode units are perpendicular to the second conductivity type electrode line The distance in the extension direction is determined according to the current spreading length. The thin film diode chip provided by the invention greatly reduces the thickness of the diode chip, improves the heat dissipation performance of the diode chip, and solves the great limitation of the diode structure in the prior art on three important parameters of lumen efficiency, lumen density output and lumen cost Due to the technical problems, the lumen output per unit area of the chip is improved, and the lumen cost is reduced.

Description

A thin film vertically integrated unit diode chip

technical field

The present invention relates to the field of semiconductor materials and device technology, in particular to semiconductor optoelectronic devices, and more particularly, to a thin-film vertically integrated unit diode chip.

Background technique

In conventional vertical structure LED chips, the current diffusion mainly depends on the n-electrode side, and there are electrode lead-type leads or drilled-type leads, but the overall current diffusion is still uneven, resulting in loss of luminous efficiency and uneven heat dissipation, thus affecting the unit. Efficiency and stability of diode chips. This limits the vertical high-power LED chips to provide products with higher lumen output per unit area. Uneven current spreading, uneven heat spreading, and uneven light extraction lead to great limitations in three important parameters: lumen efficiency, lumen density output, and lumen cost. The vertical LED chip technology currently on the market Unable to provide a valid solution.

The first prior art is the Proc.of SPIE Vol.10021 100210X-1 2016 conference paper, as shown in Figure 1-3, wherein Figure 1 is a structural diagram of a vertical LED chip, wherein the P-type electrode is connected to the back electrode (back metal Au), the box on the edge of the black part and the three finger-shaped leads in the middle represent the N-type electrodes, which are led out through the two large N-type pads below. Therefore, the current spreading of the entire chip is mainly limited by the N-type metal wires.

FIG. 2 shows the near-field analysis diagram and the normalized current distribution diagram on the center line of the vertical chip of the prior art, and the size of the chip is 1.2 mm×1.2 mm. It can be seen from the near-field image that the current distribution of the chip is still very uneven. The area close to the n-electrode line has high light intensity and high current density, while the area far from the n-electrode line has low light intensity and low current density. The normalized profile shows that the regions with smaller current density are less than 70% of the larger regions. Therefore, LED light efficiency, heat dissipation and stability under high current are severely limited.

SUMMARY OF THE INVENTION

The present invention proposes an integrated unit diode with high lumen efficiency and high lumen density output in order to solve the technical problem that the three important parameters of diode structure lumen efficiency, lumen density output and lumen cost existing in the prior art have great limitations. .

In order to achieve the above object, the present invention provides a thin film vertically integrated unit diode chip, comprising: a protective metal layer, a mirror, a second conductivity type layer, a second conductivity type electrode, a quantum well active region, a first conductivity type layer, The insulating dielectric layer, the first conductivity type electrode, and the side away from the first conductivity type electrode form n diode mesa structures and trenches, and the second conductivity type electrode lines extend along the trenches above the second conductivity type layer , n diode unit mesa structures are formed between the extended electrode lines of the second conductivity type, where n≥2; the trenches are located between the diode units; wherein, the N-type conductive electrodes of adjacent diode units are perpendicular to the electrodes The distance in the direction of line extension is less than the lateral critical current spreading length, which is the current spreading length corresponding to the inflection point on the "operating voltage (VF) - cell size" curve of the diode cell.

Preferably, the lateral critical current diffusion length is less than 70 microns.

Preferably, the growth substrate of the chip is removed by means of laser lift-off or chemical etching.

Preferably, the cross-sectional shapes of the grooves between the diode units are triangles, quadrilaterals, arcs, concentric rings, and crosses.

Preferably, the width of the groove is 0.5 nanometers to 10 micrometers, and the depth is 0.5 nanometers to 10 micrometers.

Preferably, the cross-sectional areas of the n diode units in the diode mesa structure along the vertical direction upward from the bottom of the trench and perpendicular to the extending direction of the electrode of the second conductivity type remain unchanged or gradually decrease.

Preferably, the diode units are uniformly or non-uniformly arranged on the chip.

Preferably, the electrode lines of the second conductivity type extend from the first end faces to the second end faces of the n diode units, or the second conductivity type electrode wires extend from the first end faces to the second end faces of some of the diode units.

Preferably, the electrode lines of the second conductivity type are in ohmic contact with the tops of the n diode units.

Preferably, the second conductive type pad is connected to the second conductive type electrode line; the second conductive type electrode line is a strip-shaped electrode line.

Preferably, the linear electrode line layout is partially or completely designed using a linear layout.

Preferably, the linear electrode line layout is partially or completely designed to adopt a non-linear layout, and the non-linear layout includes a broken line layout and a curved layout.

Preferably, it also includes a first conductivity type pad and a second conductivity type pad, wherein the first conductivity type pad and the second conductivity type pad are on the same side of the chip, and the first conductivity type electrode and the first conductivity type pad The second conductive type electrode is connected to the second conductive type pad, and the number of the first conductive type pad and the number of the second conductive type pad is greater than or equal to 1.

Preferably, the shapes of the first conductive type pad and the second conductive type pad are: semicircle, circle, rectangle, triangle.

Preferably, the thickness of the first conductive type pad and the second conductive type pad is 0.001 micrometers to 20 micrometers; the width of the first conductive type pads is 10 micrometers to 100 micrometers.

Preferably, the first conductive type pad and the second conductive type pad are located at any edge of the chip plane, at the apex of the chip plane, in the middle of the chip plane, or at any other position on the chip.

Preferably, the n diode units include a current blocking layer and a protective metal layer, a mirror is arranged in the protective metal layer, and the current blocking layer is embedded in the protective metal layer and the mirror.

Preferably, the contact length between the second conductivity type electrode and the second conductivity type layer is less than the length of the current blocking layer; the contact length between the second conductivity type electrode and the second conductivity type layer is 0.001 μm-30 μm; the current blocking layer Layer lengths range from 0.001 microns to 30 microns.

Preferably, the materials of the insulating dielectric layer and the current blocking layer are any one of silicon dioxide, aluminum oxide, and silicon nitride, or a combination of three insulating materials.

Preferably, the diode unit shapes are: triangles, squares, rectangles, pentagons, hexagons, circles, and any other custom shapes.

Preferably, the lengths of the n diode units along the extending direction parallel to the electrode lines of the second conductivity type are L ₀ , L ₁ , L ₂ ,...L _x ,...L _n ; the L ₀ ≥L ₁ ≥L ₂ ≥...L _x ...≥L _n ; the widths of the n diode units are W ₀ , W ₁ , W ₂ ,...W _y ,... W from the middle to the two sides along the extending direction perpendicular to the second conductive type electrode lines _n , where W _{0 ≥W 1} ≥W ₂ ≥...Wy... _≥Wn . The thin film vertically integrated unit diode chip used in the present invention breaks through the limitations of the existing vertical LED technology at the three levels of light, electricity and heat through the effect of nano-micron size structure. The size design of the unit diode chip is controlled within the current diffusion length, and the geometric optimization design method with high degree of freedom can simultaneously solve the problem of uneven current diffusion of the n-electrode and p-electrode that plagues the design of the LED unit diode chip. Higher photoelectric conversion efficiency/lumen efficiency; the nano-microstructure of each diode unit, as well as the hole structure and trench structure inside the mesa can increase the effective light extraction area, thereby improving the light extraction efficiency; laser lift-off or chemical etching is used to cut Thinning or removing the substrate greatly reduces the chip thickness. The thin film substrate of the integrated unit diode chip, the reduction in size and the hole structure inside the mesa bring a larger heat dissipation area and better heat dissipation performance, which can allow the injection of ultra-large current density without affecting its stability, thereby improving the The lumen output of the integrated unit diode chip per unit area reduces the lumen cost.

Description of drawings

FIG. 1 is a structural diagram of a diode unit in the prior art.

FIG. 2 is a structural diagram of a diode unit in the prior art.

3 is a top view of the diode mesa structure provided in Embodiment 1 of the present invention.

4 is a top view of the diode mesa structure provided in Embodiment 1 of the present invention.

5 is a cross-sectional view of a diode mesa structure provided in Embodiment 2 of the present invention.

FIG. 6 is a three-dimensional diagram of a thin-film vertically integrated unit diode chip provided in Embodiment 3 of the present invention.

FIG. 7 is a schematic diagram of a sidewall of a diode unit provided in Embodiment 3 of the present invention.

FIG. 8 is a top view of the diode unit provided in Embodiment 3 of the present invention.

FIG. 9 is a top view of the diode mesa structure provided in Embodiment 4 of the present invention.

FIG. 10 is a top view of the diode mesa structure provided in Embodiment 4 of the present invention.

11 is a top view of the diode mesa structure provided in Embodiment 5 of the present invention.

FIG. 12 is a top view of the diode mesa structure provided in Embodiment 5 of the present invention.

FIG. 13 is a top view of the diode mesa structure provided in Embodiment 6 of the present invention.

FIG. 14 is a top view of the diode mesa structure provided in Embodiment 6 of the present invention.

FIG. 15 is a top view of the diode mesa structure provided in Embodiment 6 of the present invention.

FIG. 16 is a side view of the diode unit provided in Embodiment 7 of the present invention.

FIG. 17 is a schematic diagram of a diode unit provided in Embodiment 7 of the present invention.

Fig. 18 is a schematic diagram showing the relationship between working voltage VF and cell size

19 is a schematic diagram of the VF reduction effect achieved by the present invention

Second conductivity type electrode 1, insulating dielectric layer 2, second conductivity type layer 3, quantum well active region (MQWs) 4, first conductivity type layer 5, diode mesa structure 6, trench structure 7, diode cell 8, The second conductivity type electrode line 9 , the hole structure 10 , the protective metal layer 11 , and the mirror 12 .

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In a preferred embodiment, the length of the current spreading is specifically the lateral critical current spreading length;

Wherein, the lateral critical current spreading length is the current spreading length corresponding to the inflection point on the "operating voltage (VF) - cell size" curve of the light emitting diode unit. When it is less than this critical value, the performance of the chip begins to have a huge improvement.

The included dimensions of the chip and each diode unit can be defined. The length, width and height of the chip are XYZ respectively, and the unit size is represented by abc. The specific principle is shown in Figure 18. The cell size of 100 μm refers to the conventional LED chip structure on the market, and the cell size refers to the spacing of the N-P electrodes: X=72, 60, 50, 40, and 30 μm. Curves with different colors represent different drive currents. Because the working voltage of LED chips is usually required by the market to be VF<3.3V, the current conventional LED chips can only meet the conditions under the driving current of 150mA. With the shrinking of the lateral current diffusion length, when it is less than 72μm, the VF begins to decrease rapidly, so we can define 72 μm as the critical lateral current diffusion length in the design. When it is less than this critical value, the performance of the chip begins to have a huge improvement. . For example, when the size is 50 microns, the driving current is VF<3.3V at 300mA, so the new design can allow the driving current to exceed the current conventional chip (overdrive 100%), thereby greatly improving the lumen density of the chip.

Figure 19 shows the improvement effect of the above setting on VF, which defines a critical current diffusion length, L<72μm, under such a design, due to the reduction of VF, LED chips with higher energy efficiency can be obtained; The reduction of VF, the improvement of energy conversion efficiency, and the reduction of thermal effect will also result in a chip with better stability; and due to the improvement of the uniformity of current spreading, the chip can withstand higher driving current, which greatly improves the The lumen density of the chip.

A thin film vertically integrated unit diode chip, comprising:

The first conductivity type electrode, the second conductivity type electrode, and the side away from the first conductivity type electrode form n diode mesa structures and trench structures, and the second conductivity type electrode line is along the second conductivity type layer. The trenches are extended, and n diode unit mesa structures are formed between the extended electrode lines of the second conductivity type, where n≧2; the trench structures are located between the diode units.

The diode mesa structure further includes a first conductivity type layer, a second conductivity type layer, and a quantum well active region on the first conductivity type layer, wherein the depth of the trench structure is less than or equal to the thickness of the second conductivity type layer ; The distance between adjacent diode units perpendicular to the extending direction of the electrode lines of the second conductivity type is less than the lateral critical current diffusion length.

The cross-sectional area of the n diode units is gradually reduced along the vertical direction upward from the bottom of the trench and perpendicular to the extending direction of the second conductive type electrode.

The shape of the groove between the diode units is quadrilateral, concentric ring, cross and other arbitrary curved shapes, the cross-sectional shape of the groove is triangle, quadrilateral, arc and other arbitrarily defined shapes, and the horizontal direction of the groove is unevenly distributed or uniform. Distribution, horizontally uneven distribution includes equidistant and non-equidistant periodic distribution, or equidistant and non-equidistant non-periodic distribution.

The angle α between the side wall of the diode unit and the horizontal plane is greater than 0 degree and less than or equal to 90 degrees, and the shape of the side wall is a trapezoid, a quadrilateral, a curved surface and other arbitrary defined shapes. The diode unit has at least one sidewall surface with grooves distributed from the bottom to the top of the chip. The cross-sectional shape of the grooves is triangle, quadrilateral, arc and other arbitrary defined shapes. The horizontal direction of the grooves is unevenly distributed or evenly distributed, and the grooves are horizontal The directional non-uniform distribution distribution includes equidistant and non-equidistant periodic distribution, or equidistant and non-equidistant non-periodic distribution, and the groove width is 0.5 nanometers to 1 micrometer and the depth is 0.5 nanometers to 1 micrometer.

A thin film vertically integrated unit diode chip includes electrode lines; the electrode lines are electrode connecting lines between diode units; and the electrode connecting lines are line-shaped electrode lines. The diode mesa structure includes a hole structure.

The shape of the diode unit is: triangle, square, rectangle, pentagon, hexagon, circle, and any custom shape. The number of diode units in the diode mesa structure is 2 to 100 billion. The extension direction length of the electrode lines of the second conductivity type is 0.001 micrometers to 1 micrometers. The diode units in the diode mesa structure are arranged and distributed uniformly and symmetrically.

Example 1

This embodiment provides a thin film vertically integrated unit diode chip, including: a second conductivity type electrode 1 , an integral mesa structure composed of a diode unit mesa, a trench and a diode unit 8 and a second conductivity type electrode line 9 .

As shown in FIG. 3 , the overall mesa structure includes 6 rows of 102 triangular diode units of equal size and uniform distribution, and the length of the diode units along the extending direction of the electrode lines of the second conductivity type is 0.1 μm. The diode unit mesa structure adopts a triangular arrangement, and the distance between the electrode lines 9 of the second conductivity type of adjacent units is smaller than the lateral critical current diffusion length. The diode cells are triangular in shape and distributed in a uniform symmetrical arrangement. The electrode lines are electrode connecting lines between diode units, the width of the electrode lines is 0.001-2 micrometers, and the thickness is 0.001-1 micrometers.

As shown in FIG. 4 , the overall mesa structure includes 6 rows of 52 square diode units of equal size and uniform distribution, and the length of the diode units along the extending direction of the electrode lines of the second conductivity type is 0.5 μm. The diode unit mesa structure is arranged in a rectangular shape, and the distance between the electrode lines 9 of the second conductivity type of adjacent units is smaller than the lateral critical current diffusion length. The diode cells are square in shape and distributed in a uniform symmetrical arrangement. The electrode lines are electrode connecting lines between diode units, the width of the electrode lines is 0.001-20 microns, and the thickness is 0.001-10 microns.

As shown in FIG. 4 , a hole structure 10 is added to each diode unit. The hole structure includes one hole unit, and the hole unit is a circular hole unit with a diameter of 1 nm˜0.2 μm. Pore cells are arranged symmetrically, asymmetrically, periodically, aperiodically or randomly. The shape of the hole unit can also be a triangle, a square, a rectangle, a pentagon, a hexagon, a circle, and any other defined shape, and is not limited to the shape shown in FIG. 4 .

This embodiment provides three designs of thin-film vertical integrated unit light-emitting diode mesa structures. By flexibly changing the size and shape of the diode mesa structure, the best current diffusion and heat dissipation performance under a specified operating current can be obtained, and the chip performance can be greatly improved. The current density is injected, thereby increasing the lumen output per unit area.

Example 2

This embodiment provides a thin-film vertically integrated unit diode chip. As shown in FIG. 5 , a first conductivity type layer 5 , a second conductivity type layer 3 , a quantum well active region 4 located on the first conductivity type layer, The second conductive type electrode 1 , the insulating medium layer 2 , the metal protection layer 11 and the mirror 12 . In one application, the first conductivity type layer is a p-type gallium nitride layer, the second conductivity type layer is an n-type gallium nitride layer, the second conductivity type electrode is an n-electrode, and the trench is etched to a depth of the protective metal layer 11 on. The depth of the trench can also be etched into the N-type gallium nitride layer, the quantum well active region or the P-type gallium nitride layer, which is not limited to that shown in FIG. 5 .

The growth substrate of the thin film vertically integrated unit diode chip is removed by means of laser lift-off or chemical etching, and the thickness of the thin film vertically integrated unit diode chip of the removed substrate is 8 microns.

Example 3

This embodiment provides a thin-film vertically integrated unit diode chip. As shown in FIG. 6 , the chip includes 4 rows of 30 trapezoidal diode units of equal size and uniform distribution, and the length of the diode units along the extension direction of the second conductivity type electrode line is 0.01 μm . The second conductive type electrode line spacing of adjacent cells is smaller than the diffusion length of the current injection. The diode cells are trapezoidal in shape and distributed in a uniform symmetrical arrangement. The angle between the side wall of the diode unit and the horizontal plane is greater than 0 degrees and less than or equal to 90 degrees, and the shape of the side wall of the diode unit is a trapezoid.

As shown in FIG. 7, the diode cell has a sidewall surface with trenches extending from the bottom to the top of the mesa. The cross-sectional shape of the trench on the sidewall of the diode unit is a triangle, the width of the trench on the sidewall is 0.5 nanometer-1 micrometer, and the depth is 0.5 nanometer-1 micrometer.

As shown in Figure 8, there are trenches distributed from the bottom to the top of the mesa on the four sidewalls of the diode unit. When the cross-sectional shape of the trench is a triangle, the width of the sidewall trench is 0.5nm-1µm, and the depth is 0.5nm- 1 micron.

Example 4

This embodiment provides a thin-film vertically integrated unit diode chip. As shown in FIG. 9 , the diode mesa structure includes 56 square diode units in 6 rows and a trench structure 7 , and the trench structure is located between the diode units. The diode units are uniformly distributed in the chip plane, and the length of the diode units along the extending direction of the electrode lines of the second conductivity type is 10 nanometers to 100 nanometers. The lengths of the diode units in each row along the extending direction of the electrode lines of the second conductivity type from close to the second conductivity type pad are different or equal in size. When they are _{not equal} , their _lengths are defined as _{L 0} , L ₁ , _{L 2} , _{L 3} .

In some preferred embodiments, the length of the diode unit along the extending direction of the electrode line of the second conductivity type is 2000 microns; the length of the diode unit along the extending direction of the electrode line of the second conductivity type is 100 microns; The length along the extending direction of the electrode line of the second conductivity type is 10 micrometers; in other preferred embodiments, the length of the diode along the extending direction of the electrode line of the second conductivity type is 1 micrometer.

As shown in FIG. 10 , the chip includes 6 rows of 16 squares of equal size, 40 two kinds of rectangular diode cells with equal lengths and different widths, and trench structures 7 , and the trench structures are located between the diode cells. The diode units in each row are of equal size, the diode units are evenly distributed, and the width of each diode unit along the y-axis direction is 10 nanometers to 100 nanometers. The diode cells start from the middle and have unequal or equal widths along the y-axis. When they are _not equal, the _widths from the middle to the _two sides are defined as W ₀ , W ₁ , _{W 2} , _{W 3} . _m .

Example 5

This embodiment provides a thin-film vertically integrated unit diode chip. As shown in FIG. 11 , it includes 19 columns and a total of 22 rectangular diode units of equal size and part, which are uniformly symmetrically arranged and distributed. The diode units extend along the second conductivity type electrode line. The length of the direction is 50 microns. The diode mesa structure is arranged in a rectangular shape, and the distance between the n electrodes of adjacent units is smaller than the current diffusion length. The electrode line 1 of the second conductivity type is in contact with the top of the 22 diode units, and the shape of the contact surface is rectangular. The electrode lines of the second conductivity type are perpendicular to the trenches between the diode cells in each column. The number of the second conductive type pads is 1, and the shape is an irregular polygon with an arc-shaped side, which is located at the edge of the short side of the chip plane. The second conductive type pad has a thickness of 1 micrometer and a width of 50 micrometers.

As shown in FIG. 12 , it includes 7 rows of 85 square diode units with equal size and uniform arrangement, and the length of the diode units along the extending direction of the electrode lines of the second conductivity type is 10 μm. The diode mesa structure is arranged in a rectangular shape, and the size of the mesa structure is smaller than the diffusion length of the current. The electrode line 1 of the second conductivity type is in ohmic contact with the top of the 85 diode units, and the shape of the contact surface is rectangular. The electrode lines of the second conductivity type are perpendicular to the trenches between the diode cells in each row. The number of the second conductive type pads is 1, the shape is hexagonal, and the pads are located at the short edge of the mesa structure. The second conductive type pad has a thickness of 2 microns and a width of 100 microns.

Example 6

This embodiment provides a thin film vertically integrated unit diode chip, including: a second conductivity type electrode 1, a second conductivity type pad, a first conductivity type pad, a line-type electrode line, a diode mesa structure, a diode cell and a trench . The diode mesa structure includes 6 rows of 52 square diode units of equal size and uniform distribution, and the length of the diode units along the extension direction of the electrode lines of the second conductivity type is 40 microns. The diode mesa structure adopts a square arrangement, the diode units are connected in parallel, and the size of the mesa structure is smaller than the diffusion length of the current injection. The diode unit is rectangular in shape and distributed in a uniform and symmetrical arrangement. The second conductivity type electrode is an n electrode, the first conductivity type pad is a p pad, and the second conductivity type pad is an n pad.

In some preferred embodiments, the length of the diode unit along the extension direction of the second conductivity type electrode line is 100 microns; in other preferred embodiments, the length of the diode unit along the extension direction of the second conductivity type electrode line is 10 microns; In a preferred embodiment, the length of the diode along the extending direction of the electrode line of the second conductivity type is 1 micrometer.

The first conductive type pad and the second conductive type pad are on the same side of the mesa structure, and the second conductive type electrode 1 and the second conductive type pad are connected by line-shaped electrode lines.

As shown in FIG. 13 , the shapes of the second conductivity type pads and the first conductivity type pads are both irregular polygons with an arc-shaped side, and the number of the second conductivity type pads and the first conductivity type pads are both 1 , located on the short edge of the mesa structure.

As shown in FIG. 14 , the shape of the second conductivity type pad and the first conductivity type pad are both irregular polygons with an arc-shaped side, and the shape of the pads can also be semicircle, circle, rectangle, triangle, etc. Regular rectilinear polygons, or other irregular polygons whose one or more sides are arc-shaped, are not limited to those shown in FIG. 14 . The number of the second conductive type pad and the first conductive type pad is 1, the second conductive type pad is located on the short edge of the mesa structure, and the first conductive type pad is located on the long edge of the mesa structure.

As shown in FIG. 15 , the pad of the second conductivity type is an irregular polygon with an arc-shaped side, located at the short edge of the mesa structure, and the pad of the first conductivity type is a regular hexagon and is located at the vertex of the mesa. The numbers of the second conductive type pads and the first conductive type pads are both 1.

The thickness of the pad is 0.001 micrometers to 20 micrometers, and the width is: 10 micrometers to 100 micrometers. The width of the electrode lines is 0.001-20 micrometers, and the thickness is 0.001-10 micrometers, the electrode lines are made of indium tin oxide material, and the linear layout is designed. The shape of the grooves is cross-shaped, the cross-sectional shape is rectangular, and the horizontal direction is evenly distributed.

Example 7

As shown in FIGS. 16 and 17 , the n diode units include a first conductivity type layer 5 , a second conductivity type layer 3 , and a quantum well active between the first conductivity type layer 5 and the second conductivity type layer 3 . Region 4, insulating dielectric layer 2, current blocking layer, mirror, protective metal layer, and back electrode 16. The first conductive type layer 5 is a P-type gallium nitride layer, and the second conductive type layer 3 is an N-type gallium nitride layer. A mirror is arranged in the protective metal layer, a part of the current blocking layer is embedded in the mirror, and the other part is embedded in the protective metal layer, and the current blocking layer and the upper surface of the mirror are in contact with the P-type gallium nitride layer. The insulating dielectric layer 2 is located on the protective metal layer and is in contact with the N-type gallium nitride layer, and the n-electrode is located on the insulating dielectric layer 2 and is in contact with the N-type gallium nitride layer. The length of the current blocking layer is 1 micrometer, and the contact length between the n electrode and the N-type gallium nitride layer is 0.1 micrometer, which is less than the length of the current blocking layer. The material of the insulating medium layer and the current blocking layer is any one of silicon dioxide, aluminum oxide, and silicon nitride. Mirror materials are silver, aluminum or distributed Bragg reflectors. The protective metal layer material is aluminum, silver, titanium, nickel, gold, platinum, chromium, tin, tungsten. The back electrode material is aluminum, silver, titanium, nickel, gold, platinum, chromium, tin, or an alloy of any two or more of the above metals.

Since the current diffusion length of the diode chip is inversely proportional to the square root of the current density, under the injection of a large current, the current diffusion length is shorter, resulting in more uneven current diffusion of the chip, lower efficiency, and more difficult heat dissipation. Using thin-film vertical integrated unit light-emitting diode structure design, the size and shape of the diode mesa structure can be flexibly changed, the best current diffusion and heat dissipation performance under the specified operating current can be obtained, and the injection current density of the chip can be greatly improved. Lumen output per unit area.

The thin-film vertically integrated unit light-emitting diode provided by the embodiment of the present invention has the following beneficial effects:

(1) The design of the n-electrode spacing of adjacent diode units in the present invention is controlled within the current diffusion length, and the optimized geometric design with a certain degree of freedom can further improve the light extraction efficiency, and can simultaneously solve the second problem that plagues the LED unit diode chip design. The problem of uneven current diffusion between the conductive type electrode and the first conductive type electrode, so as to obtain higher photoelectric conversion efficiency/lumen efficiency;

(2) The micro-nano structure of each diode unit of the present invention increases the light emitting area of the sidewall, thereby improving the light extraction efficiency;

(3) The optimization of the chip size of the integrated unit diode of the present invention brings a larger heat dissipation area of the sidewall, has better heat dissipation performance, allows the injection of a large current density without affecting its stability, and greatly improves the unit area. The lumen output of the unit diode chip reduces the lumen cost;

(4) The design of the integrated unit diode chip of the present invention can realize ultra-uniform current injection, thereby obtaining higher efficiency, better wavelength uniformity, narrower half-width of the emission spectrum, and better heat dissipation uniformity. performance and better device stability.

(5) The integrated unit diode chip of the present invention is suitable for LED products of various color systems such as UVC, UVA, UVB, purple light, blue light, green light, yellow light, red light, infrared light, etc., and can be used for LED lighting, backlight, display, plant Lighting, medical and other semiconductor light-emitting device applications. The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned specific embodiments are only specific embodiments of the present invention, and are not intended to limit the protection of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (21)

1. a thin-film vertically integrated unit diode chip, characterized in that, the diode chip sequentially comprises: a protective metal layer, a mirror, a first conductivity type layer, a quantum well active region, a second conductivity type layer electrode, the The diode chip further includes an insulating medium layer, a first conductivity type electrode, a second conductivity type electrode, and a side away from the first conductivity type electrode to form n diode mesa structures and trenches, and the second conductivity type electrode line runs along the first conductivity type electrode. The trenches on the conductive type layer are extended, and n diode unit mesa structures are formed between the extended electrode lines of the second conductivity type, where n≥2; the trenches are located between the diode units; Wherein, the distance between adjacent diode units in the direction perpendicular to the extension direction of the second conductivity type electrode line is less than the lateral critical current diffusion length, and the lateral critical current diffusion length is equal to the “operating voltage (VF) of the diode unit-cell size. ” is the current spreading length corresponding to the inflection point on the curve. 2 . The thin film vertically integrated unit diode chip of claim 1 , wherein the lateral critical current diffusion length is less than 70 μm. 3 . 3 . The thin-film vertically integrated unit diode chip according to claim 1 , wherein the growth substrate of the chip is removed by means of laser lift-off or chemical etching. 4 . 4 . The thin-film vertically integrated unit diode chip according to claim 1 , wherein the cross-sectional shapes of the trenches between the diode units are triangles, quadrilaterals, arcs, concentric rings, and crosses. 5 . 5 . The thin-film vertically integrated unit diode chip according to claim 1 , wherein the trench has a width of 0.5 nanometers to 10 micrometers and a depth of 0.5 nanometers to 10 micrometers. 6 . 6 . The thin-film vertically integrated unit diode chip according to claim 1 , wherein the n diode units in the diode mesa structure are in a vertical direction up from the bottom of the trench and perpendicular to the second The cross-sectional area in the extending direction of the conductive type electrode is unchanged or gradually reduced. 7 . The thin-film vertically integrated unit diode chip of claim 1 , wherein the diode units are uniformly or non-uniformly arranged on the chip. 8 . 8 . The thin-film vertically integrated unit diode chip according to claim 1 , wherein the electrode lines of the second conductivity type extend from the first end face of the n diode units to the second end face, or the second conductivity type electrode. 9 . A line extends from the first end face to the second end face of the portion of the diode cell. 9 . The thin-film vertically integrated unit diode chip of claim 8 , wherein the electrode lines of the second conductivity type are in ohmic contact with the tops of the n diode units. 10 . 10 . The thin-film vertically integrated unit diode chip according to claim 9 , wherein the second conductive type pad is connected to the second conductive type electrode line; the second conductive type electrode line is a linear electrode line. 11 . . 11 . The thin-film vertically integrated unit diode chip according to claim 10 , wherein the linear electrode line layout is partially or completely designed using a linear layout. 12 . 12 . The thin-film vertically integrated unit diode chip according to claim 10 , wherein the linear electrode line layout is partially or completely designed using a non-linear layout, and the non-linear layout includes a broken line layout, a curved line layout, and a curved line layout. layout. 13. A thin film vertically integrated unit diode chip as claimed in claim 1, further comprising a first conductivity type pad and a second conductivity type pad, wherein the first conductivity type pad and the second conductivity type pad The pads are on the same side of the chip, the first conductivity type electrodes are connected to the first conductivity type pads, the second conductivity type electrodes are connected to the second conductivity type pads, the number of the first conductivity type pads and the second conductivity type pads are The number of conductive type pads is greater than or equal to 1. 14. A thin-film vertically integrated unit diode chip according to claim 13, wherein the shape of the first conductive type pad and the second conductive type pad is: semicircle, circle, rectangle ,triangle. 15 . The thin-film vertically integrated unit diode chip according to claim 13 , wherein the first conductive type pad and the second conductive type pad have a thickness of 0.001 μm˜20 μm; The width of a conductive type pad is: 10 microns to 100 microns. 16 . The thin-film vertically integrated unit diode chip of claim 13 , wherein the first conductive type pad and the second conductive type pad are located at any edge of the chip plane or at the apex of the chip plane. 17 . , the middle of the chip plane or any other position on the chip. 17 . The thin-film vertically integrated unit diode chip according to claim 1 , wherein the n diode units comprise a current blocking layer and a protective metal layer, wherein a mirror is arranged in the protective metal layer, and the current The blocking layer is embedded in the protective metal layer and the mirror. 18 . The thin-film vertically integrated unit diode chip according to claim 17 , wherein the contact length between the second conductivity type electrode and the second conductivity type layer is less than the length of the current blocking layer; the second conductivity type electrode The length of the contact with the second conductive type layer is 0.001 micrometers to 30 micrometers; the length of the current blocking layer is 0.001 micrometers to 30 micrometers. 19. A thin-film vertically integrated unit diode chip according to claim 17, wherein the insulating dielectric layer and the current blocking layer are made of any one or three of silicon dioxide, aluminum oxide, and silicon nitride. A combination of insulating materials. 20 . The thin-film vertically integrated unit diode chip of claim 17 , wherein the diode unit shape is: triangle, rectangle, pentagon, hexagon, circle, or any other custom shape. 21 . 21 . The thin-film vertically integrated unit diode chip according to claim 7 , wherein the lengths of the n diode units along the extending direction parallel to the second conductive type electrode lines are L ₀ , L ₁ , and L 21 . ₂ ,...L _x ,...L _n ; the L ₀ ≥L ₁ ≥L ₂ ≥...L _x ...≥L _n ; the n diode units extend from the middle along the extending direction perpendicular to the second conductive type electrode line The widths to both sides are W ₀ , W ₁ , W ₂ ,...W _y ,...W _n , where W ₀ ≥W ₁ ≥W ₂ ≥...W _y ...≥W _n .

Images