TWI624080B - Light emitting diode chip - Google Patents

Abstract

A light emitting diode wafer is disclosed herein. The light emitting diode chip includes a substrate and a semiconductor stack formed on the substrate and including a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer, the semiconductor stack having a first side and disposed under the first side a second surface, wherein the first side is an outer side of the semiconductor stack etched by the platform, the second side is an outer side of the first conductive type semiconductor layer, and at least one of the first side and the second side has a convex pattern . Therefore, the light-emitting diode wafer of the present invention can improve lateral light extraction by a convex pattern.

Description

Light-emitting diode chip

The present invention relates to a light-emitting diode wafer, and more particularly to a light-emitting diode wafer capable of improving light-emitting efficiency.

A typical light emitting diode wafer includes a semiconductor stack formed over a substrate (eg, a sapphire substrate), and electrodes formed over the semiconductor stack. In order to overcome the light loss of a general light-emitting diode wafer due to the total reflection of light generated in the active layer in the semiconductor stack, a convex-concave pattern structure on the substrate is thus proposed. However, this structure still has a problem of deterioration of light loss due to total reflection.

One aspect of the present invention provides a light emitting diode wafer capable of improving a light emitting effect.

According to an aspect of the invention, a light emitting diode wafer includes: a substrate; and a semiconductor stack formed on the substrate and including a first conductive type semiconductor layer, a main And a second conductive type semiconductor layer, the semiconductor stack has a first side and a second side disposed under the first side, wherein the first side is an outer side of the semiconductor stack for mesa-etching, The two sides are outer sides of the first conductive semiconductor layer, and at least one of the first side and the second side has a convex pattern. Therefore, the light-emitting diode wafer of the present invention can improve lateral light extraction by a convex pattern.

At least one of the first side and the second side further includes a concave pattern. The concave pattern includes a flat plate shape, and the concave pattern and the convex pattern are staggered.

Each of the first side and the second side further includes a concave pattern. The concave pattern includes a flat plate shape, and the concave pattern and the convex pattern are staggered.

At least one of the first side and the second side includes a microlens pattern. The microlens pattern is staggered with the convex pattern.

The convex pattern may include at least two of a circular protruding pattern, a triangular protruding pattern, and a rectangular protruding pattern, which are staggered with each other.

At least one of the first side and the second side may further include a concave pattern. The concave pattern includes a circular groove shape, and the concave pattern and the convex pattern are staggered.

Each of the first surface and the second side may have a fixed angle of inclination.

The first conductive type semiconductor layer may further include a third side surface formed on the second side surface at an outer side surface of the first conductive type semiconductor layer.

The convex pattern may include a first convex pattern on the first side; a second convex pattern above the second side; and a third convex pattern above the third side.

The first side may include a first planar pattern staggered with the first convex pattern, the second side may include a second planar pattern staggered with the second convex pattern, and the third side may include a staggered arrangement with the third convex pattern The third planar pattern.

The light emitting diode chip may further include a transparent electrode layer located above the second conductive type semiconductor layer. Here, the outer side of the transparent electrode layer is included in the first side.

The first side may correspond to a region formed by etching the transparent electrode layer and the semiconductor stack by the platform.

The first side may have a shape corresponding to an edge of the mask for platform etching.

The second side may correspond to a region of the first conductive type semiconductor layer etched in the unit cell dividing process.

The second side may have a shape corresponding to an edge of the mask for the unit cell division process.

According to an embodiment of the present invention, a light-emitting diode wafer reduces total reflection of light on one side thereof by a convex pattern, thereby providing excellent light extraction efficiency, and the convex pattern is formed by etching a transparent electrode layer and a semiconductor stack by mesa The formed first side surface and at least one of the second side surfaces formed by etching the first conductive type semiconductor layer by using a cell division process.

In addition, the light emitting diode wafer has a planar pattern and a convex surface staggered with the convex pattern positioned above at least one of the first side surface and the second side surface A concave pattern in which the patterns are staggered, a microlens pattern staggered with the concave pattern, or a triangular pattern staggered with the convex pattern to provide excellent light extraction efficiency.

With these structures of the first side and the second side, the light-emitting diode wafer of the present invention has improved light extraction efficiency, thereby improving luminous efficiency.

100, 200, 300, 400‧‧‧Light Emitting Diode Wafers

110‧‧‧Substrate

111‧‧‧ convex-concave pattern

120‧‧‧First Conductive Semiconductor Layer

130‧‧‧Active layer

140‧‧‧Second conductive semiconductor layer

150‧‧‧Transparent electrode layer

160, 260, 460, 560, 660, 760‧‧‧ second side

First side of 170, 470, 570, 670, 770‧‧

171, 261, 361, 461, 471, 561, 571 ‧ ‧ concave pattern

173, 263, 363, 463, 473, 563, 573, 663, 673, 773, 761, 763, 771 ‧ ‧ convex patterns

180‧‧‧First electrode

190‧‧‧second electrode

360‧‧‧ third side

661, 671‧‧‧ microlens pattern

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic plan view of a light emitting diode wafer in accordance with a first embodiment of the present invention.

Figure 2 is a cross-sectional view of the light-emitting diode wafer of Figure 1 along line I-I'.

Figure 3 is a schematic plan view of a light emitting diode wafer in accordance with a second embodiment of the present invention.

Figure 4 is a cross-sectional view of the light-emitting diode wafer of Figure 1 along line I-I'.

Figure 5 is a schematic plan view of a light emitting diode wafer in accordance with a third embodiment of the present invention.

Figure 6 is a cross-sectional view of the light-emitting diode wafer of Figure 1 along line I-I'.

Figure 7 is a schematic plan view of a light emitting diode wafer in accordance with a fourth embodiment of the present invention.

Figure 8 is a cross-sectional view of the light emitting diode chip taken along line I-I' of Figure 7.

9 through 11 are schematic views of a light emitting diode wafer in accordance with other embodiments of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. It is to be understood that the embodiments of the invention below are merely provided to those skilled in the art. Therefore, the present invention is not limited to the embodiments below and when different operations are possible. In addition, similar components will be denoted by the same reference numerals in the description, and the width, length and thickness of some elements, layers or features may be exaggerated for clarity.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic plan view of a light-emitting diode wafer according to a first embodiment of the present invention, and Figure 2 is a cross-sectional view of the light-emitting diode wafer of Figure 1 along line I-I'.

Referring to FIG. 1 and FIG. 2, a light emitting diode wafer 100 according to a first embodiment of the present invention includes a substrate 110, a semiconductor stack, a transparent electrode layer 150, a first electrode 180, and a second electrode 190.

The substrate 110 may be a growth substrate for growth of a gallium nitride based compound semiconductor layer, such as a sapphire substrate, a spinel substrate, a gallium nitride substrate, or tantalum carbide. A (silicon carbide) substrate or a silicon substrate, the related materials are not limited.

The substrate 110 includes a convex-concave pattern 111 formed on an upper surface thereof. The convex-concave pattern 111 is provided to improve luminous efficacy. The convex-concave pattern 111 refracts light directed toward the surface of the substrate 110 to the outside of the substrate. The convex-concave pattern 111 is formed to protrude into a strip-shaped semi-cylindrical shape.

Although the convex-concave pattern 111 is drawn to have a protruding strip-shaped semi-cylindrical shape, It should be understood that this is not intended to limit the invention. In addition, the convex-concave pattern 111 may be an island-shaped semi-spherical shape or other polygonal shape.

The semiconductor stack includes a first conductive type semiconductor layer 120, an active layer 130, and a second conductive type semiconductor layer 140.

The active layer 130 is interposed between the first conductive type semiconductor layer 120 and the second conductive type semiconductor layer 140, and may have a single quantum well structure or a multi-quantum well structure. The constituent elements and proportions of the active layer 130 are determined to emit light having a desired wavelength, such as ultraviolet (UV) or visible light.

The first conductive type semiconductor layer 120 may include N-type gallium nitride (GaN), and the second conductive type semiconductor layer 140 may include P-type gallium nitride. Further, the first and second conductive semiconductor layers may be formed of P-type and N-type GaN, respectively. The first conductive semiconductor layer 120 and the second conductive semiconductor layer 140 may be formed in a single layer or a plurality of layers, respectively.

The active layer 130, the first conductive semiconductor layer 120, and the second conductive semiconductor layer 140 may be formed by metalorganic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). .

The transparent electrode layer 150 is formed over the second conductive type semiconductor layer 140. The transparent electrode layer 150 may be formed of a transparent oxide such as indium tin oxide (ITO), zinc oxide (ZnO), Fluorine-doped Tin Oxide (FTO), gallium doped zinc oxide (gallium doped). Zinc oxide, GZO), graphene, carbon nanotube (CNT), nickel/gold, etc. Like the substance, the transparent electrode layer 150 forms an ohmic contact with the second conductive type semiconductor layer 140. Although not shown in the drawings, a current blocking layer (not shown) may be formed between the transparent electrode layer 150 and the second conductive type semiconductor layer 140. The current blocking layer is provided to enhance current spreading between the transparent electrode layer 150 and the second conductive type semiconductor layer 140.

In the light-emitting diode wafer 100, the first conductive semiconductor layer 120 and the transparent electrode layer 150, the second conductive semiconductor layer 140, and the active layer 130 are partially etched together by platform etching to expose the first conductive semiconductor. Layer 120. The transparent electrode layer 150 and the platform-etched outer side of the semiconductor stack are defined as a first side 170. The first side surface 170 is formed with a convex pattern 173 and a concave pattern 171 which enhance lateral light extraction efficiency.

The convex pattern 173 and the concave pattern 171 are alternately formed along the first side surface 170, and the convex pattern 173 has a rounded shape. The convex pattern 173 and the concave pattern 171 can be formed in a mask process using photoresist. In other words, the outer side surface of the mask (not shown) has the same shape as the convex pattern 173 and the concave pattern 171.

The light-emitting diode wafer 100 is divided into unit cells on the substrate 110, and the unit cells are separated from each other by cutting, thereby providing a single light-emitting diode wafer 100, as shown in FIGS. 1 and 2.

Here, in the step of dividing the light-emitting diode wafer 100 into unit cells, the first conductive type semiconductor layer 120 is also divided into unit cells by etching, and thus the upper surface of the substrate 110 may be in the first conductive type semiconductor layer 120. The edges are exposed.

The outer side surface of the first conductive type semiconductor layer 120 divided into unit cells is defined as a second side surface 160. The second side 160 has a flat structure.

In the above-described light emitting diode wafer 100 according to the first embodiment of the present invention, the convex pattern 173 and the concave pattern 171 are alternately formed on the transparent electrode layer 150 and the first side surface 170 of the semiconductor stack, thereby reducing the light emission The total reflection of the side faces of the polar body wafer 100 allows the light-emitting diode wafer to have excellent light extraction.

3 is a schematic plan view of a light-emitting diode wafer according to a second embodiment of the present invention, and FIG. 4 is a cross-sectional view of the light-emitting diode wafer cut along line I-I' of FIG.

As shown in FIG. 3 and FIG. 4, the light-emitting diode wafer 200 according to the second embodiment of the present invention and the light-emitting diode wafer 100 (refer to FIG. 1) according to the first embodiment of the present invention are apart from the second side surface 260. Have the same structure. Therefore, the same components will be denoted by the same reference numerals, and the description of the details will be omitted herein.

The first side surface 170 includes a first convex pattern 173 and a first concave pattern 171. The convex pattern 173 and the concave pattern 171 are alternately formed along the first side surface 170.

The second side surface 260 is defined by the outer side surface of the first conductive type semiconductor layer 120 and includes a second convex pattern 263 and a second concave pattern 261. The second convex pattern 263 and the second concave pattern 261 are alternately formed along the second side 260. The second convex pattern 263 and the second concave pattern 261 are provided to improve lateral light extraction of the light emitting diode wafer 300. The second convex pattern 263 has a rounded shape. The second convex pattern 263 and the second concave pattern 261 may be formed in a mask process using photoresist. In other words, the outer side surface of the mask (not shown) has the same shape as the second convex pattern 263 and the second concave pattern 261. The second convex pattern 263 and the second concave pattern 261 are formed by a cell division process.

In the light emitting diode wafer 200 according to the second embodiment of the present invention, the first convex pattern 173 and the first concave pattern 171 are alternately formed on the first side surface 170, which etches the transparent electrode layer 150 and the semiconductor stack by the platform. Formed, and the second convex pattern 263 and the second concave pattern 261 are alternately formed on the second side surface 260 of the first conductive type semiconductor layer 120 etched by the cell division process, thereby reducing the side surface of the light emitting diode wafer 200 The total reflection, so that the light-emitting diode wafer has excellent light extraction.

Figure 5 is a schematic plan view of a light-emitting diode wafer according to a third embodiment of the present invention, and Figure 6 is a cross-sectional view of the light-emitting diode wafer cut along line I-I' of Figure 5 .

As shown in FIG. 5 and FIG. 6, a light-emitting diode wafer 300 according to a third embodiment of the present invention and a light-emitting diode wafer 100 (refer to FIG. 1) according to the first embodiment of the present invention are provided with the second side 260 and the The three sides 360 have the same structure. Therefore, the same components will be denoted by the same reference numerals, and the description of the details will be omitted herein.

The first side surface 170 includes a first convex pattern 173 and a first concave pattern 171. The first convex pattern 173 and the first concave pattern 171 are alternately formed along the first side surface 170.

The second side surface 260 is defined as an outer side surface of the first conductive type semiconductor layer 120 and includes a second convex pattern 263 and a second concave pattern 261. The second convex pattern 263 and the second concave pattern 261 are alternately formed along the second side 260. The second convex pattern 263 and the second concave pattern 261 are provided to improve the horizontal direction of the LED wafer 300 Extract to light. The second convex pattern 263 has a rounded shape.

The third side surface 360 is defined as an outer side surface of the first conductive type semiconductor layer 120 and is disposed on the second side surface 260. The third side 360 includes a third convex pattern 363 and a third concave pattern 361. The third convex pattern 363 and the third concave pattern 361 are alternately formed along the third side 360. The third convex pattern 363 and the third concave pattern 361 are provided to improve lateral light extraction of the light emitting diode wafer 300. The third convex pattern 363 has a rounded shape.

The second convex pattern 263, the second concave pattern 261, and the third convex pattern 363 and the third concave pattern 361 may be formed in a mask process using photoresist. In other words, the outer side surface of the mask (not shown) has the same shape as the second convex pattern 263, the second concave pattern 261, the third convex pattern 363, and the third concave pattern 361. The second convex pattern 263, the second concave pattern 261, the third convex pattern 363, and the third concave pattern 361 are formed by a unit cell division process. Here, the second convex pattern 263, the second concave pattern 261, the third convex pattern 363, and the third concave pattern 361 may be formed by a single mask process. In other words, the second convex pattern 263, the second concave pattern 261, the third convex pattern 363, and the third concave pattern 361 may be formed using a diffraction mask or a halftone mask.

In the above-described light emitting diode wafer 300 according to the third embodiment of the present invention, the first convex pattern 173 and the first concave pattern 171 are alternately formed on the first side surface 170, which etches the transparent electrode layer 150 and the semiconductor by the terrace. Formed by the stack, the second convex pattern 263 and the second concave pattern 261 are alternately formed on the second side 260 of the first conductive semiconductor layer 120 etched by the cell division process, and The three convex surface pattern 363 and the third concave surface pattern 361 are alternately formed on the third side surface 360, thereby reducing total reflection at the side surface of the light emitting diode wafer 300, thereby providing excellent light extraction of the light emitting diode wafer.

Figure 7 is a schematic plan view of a light-emitting diode wafer in accordance with a fourth embodiment of the present invention, and Figure 8 is a cross-sectional view of the light-emitting diode wafer cut along line I-I' of Figure 7.

As shown in FIG. 7 and FIG. 8, a light-emitting diode wafer 400 according to a fourth embodiment of the present invention and a light-emitting diode chip 200 (refer to FIG. 3) according to the second embodiment of the present invention are provided with the first side 470 and the The two sides 460 have the same structure. Therefore, the same components will be denoted by the same reference numerals, and the description of the details will be omitted herein.

The first side surface 470 includes a first convex pattern 473 and a first concave pattern 471. The first convex pattern 473 and the first concave pattern 471 are alternately formed along the first side surface 470. The first side 470 has a fixed angle of inclination.

The second side surface 460 includes a second convex pattern 463 and a second concave pattern 461. The second convex pattern 463 and the second concave pattern 461 are alternately formed along the second side 460. The second side 460 has a fixed angle of inclination.

In the LED array 400 according to the fourth embodiment of the present invention, the first convex pattern 473 and the first concave pattern 471 are alternately formed on the first side surface 470, which etches the transparent electrode layer 150 and the semiconductor stack by the platform. Formed, the second convex pattern 463 and the second concave pattern 461 are alternately formed on the second side 460 of the first conductive semiconductor layer 120 etched by the cell division process, and first The side surface 470 and the second side surface 460 have a fixed tilt angle to improve lateral light extraction of the light emitting diode wafer 100.

9 through 11 are schematic views of a light emitting diode wafer in accordance with other embodiments of the present invention.

Referring to FIG. 9, the first electrode 570 of the transparent electrode layer and the semiconductor stack includes a first convex pattern 573 and a first concave pattern 571, and the second side 560 of the first conductive semiconductor layer etched by the cell division process includes a second The convex pattern 563 and the second concave pattern 561.

The first convex pattern 573 and the second convex pattern 563 have a rounded shape, and the first concave pattern 571 and the second concave pattern 561 have a circular groove shape. That is, the first side 570 and the second side 560 have a wavy pattern.

The first side 570 and the second side 560 can improve lateral light extraction of the LED wafer by a wavy pattern.

In the present embodiment, the wavy pattern is formed on the first side 570 and the second side 560 as described. However, it is not intended to limit the invention, and a wavy pattern may be formed on at least one of the first side 570 and the second side 560.

Referring to FIG. 10, the first side 670 of the transparent electrode layer and the semiconductor stack include a first convex pattern 673 and a first microlens pattern 671, and the second side 660 of the first conductive semiconductor layer etched by the cell division process includes The second convex pattern 663 and the second microlens pattern 661.

The first convex pattern 673 and the first microlens pattern 671 formed on the first side 670 and the second convex pattern 663 formed on the second side 660 And the second microlens pattern 661, the light emitting diode wafer improves lateral light extraction.

In the present embodiment, the first convex pattern 673 and the first microlens pattern 671 are formed on the first side 670 as described above, and the second convex pattern 663 and the second microlens pattern 661 are formed on the second side 660 as described. However, the present invention is not limited thereto, and these patterns may be formed only on one of the first side 670 and the second side 660.

Referring to FIG. 11 , the first electrode 770 of the transparent electrode layer and the semiconductor stack includes a first convex pattern 773 and a second convex pattern 771 , and the second side 760 of the first conductive semiconductor layer etched by the cell division process includes a third surface. The convex pattern 763 and the fourth convex pattern 761.

The first convex pattern 773 and the third convex pattern 763 have a circular protruding pattern, and the second convex pattern 771 and the fourth convex pattern 761 have a triangular protruding pattern.

The light-emitting diode wafer improves lateral light extraction by the first convex pattern 773 and the second convex pattern 771 and the third convex pattern 763 and the fourth convex pattern 761 formed on the first side 770 and the second side 760.

In this embodiment, although the first convex pattern 773 and the second convex pattern 771 and the third convex pattern 763 and the fourth convex pattern 761 are respectively formed on the first side 770 and the second side 760, the present invention Not limited thereto, these patterns may be formed only on one of the first side 770 and the second side 760. Further, although the convex pattern has a circular shape or a triangular shape as described, the shape of the convex pattern can be adjusted as much as long as it can provide a function of light extraction.

While some embodiments and features of the invention are disclosed above, it is not intended to limit the invention, and various modifications may be made without departing from the scope of the invention.

Claims (14)

A light emitting diode wafer comprising: a substrate; a semiconductor stack formed on the substrate, comprising a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer, the semiconductor stack having a first side and being disposed on a second surface below the first side surface, wherein the first side surface is an outer surface of the semiconductor stack by a platform, and the second side surface is an outer side surface of the first conductive type semiconductor layer, and At least one of the first side surface and the second side surface has a convex pattern; and a transparent electrode layer is formed over the second conductive type semiconductor layer, and the outer surface of the transparent electrode layer is included in the first In a side surface, a portion of the convex pattern is formed on the outer side surface of the transparent electrode layer, and the portion of the convex pattern surrounds the transparent electrode layer. The illuminating diode chip of claim 1, wherein at least one of the first side and each of the two sides further comprises a concave pattern, the concave pattern comprising a flat shape, the concave pattern Interlaced with the convex pattern. The light-emitting diode wafer of claim 1, wherein each of the first side surface and the two side surfaces further comprises a concave pattern, the concave surface pattern comprising a flat plate shape, the concave surface pattern and the concave surface pattern The convex patterns are staggered. The illuminating diode chip of claim 1, wherein at least one of the first side surface and the second side surface comprises a microlens pattern, and the microlens pattern is staggered with the convex pattern . The light emitting diode chip of claim 1, wherein the convex pattern comprises at least two of a circular protruding pattern, a triangular protruding pattern, and a rectangular protruding pattern, which are staggered with each other. The light emitting diode chip of claim 1, wherein at least one of the first side surface and the second side surface further comprises a concave pattern, the concave surface pattern comprising a circular groove shape, The concave pattern is staggered with the convex pattern. The light-emitting diode wafer of claim 1, wherein the first surface and the second side have a fixed tilt angle. The illuminating diode chip according to claim 1, wherein the first conductive semiconductor layer further includes a second surface formed on an outer side surface of the first conductive semiconductor layer Three sides. The illuminating diode chip of claim 7, wherein the convex pattern comprises: a first convex pattern on the first side; a second convex pattern on the second side; A third convex pattern is located on the third side. The illuminating diode chip of claim 9, wherein the first side surface comprises a first concave pattern staggered with the first convex pattern, and the second side includes the second convex surface a second concave pattern in which the patterns are staggered, and the third side includes a third concave pattern staggered with the third convex pattern. The light emitting diode chip of claim 1, wherein the first side corresponds to a region formed by etching the transparent electrode layer and the semiconductor stack by a platform. The light-emitting diode wafer of claim 11, wherein the first side has a shape corresponding to an edge of a mask for etching the platform. The light-emitting diode wafer according to claim 1, wherein the second side corresponds to a region of the first conductive type semiconductor layer etched by a cell division process. The light-emitting diode wafer of claim 12, wherein the second side has a shape corresponding to an edge of a mask for the unit cell division process.