阅读说明：本技术 一种半导体发光元件 (Semiconductor light-emitting element ) 是由 贾月华 柯韦帆 王笃祥 于 2019-09-25 设计创作，主要内容包括：一种半导体发光元件,其包括半导体发光序列,半导体发光序列包括第一导电类型半导体层、发光层和第二导电类型半导体层,第二导电类型半导体层一侧为出光面,其特征在于:出光面上包括多个独立凹槽,凹槽的底部位于第二导电类型半导体层中,凹槽之外的出光面的区域为光透射阻挡区域,所述的凹槽的侧壁相对于半导体发光序列的厚度方向倾斜的。(A semiconductor light-emitting element comprises a semiconductor light-emitting sequence, wherein the semiconductor light-emitting sequence comprises a first conduction type semiconductor layer, a light-emitting layer and a second conduction type semiconductor layer, and one side of the second conduction type semiconductor layer is a light-emitting surface.)

1. A semiconductor light-emitting element comprises a semiconductor light-emitting sequence, wherein the semiconductor light-emitting sequence comprises a first conduction type semiconductor layer, a light-emitting layer and a second conduction type semiconductor layer, and one side of the second conduction type semiconductor layer is a light-emitting surface.

2. The light-emitting element according to claim 1, wherein: the groove is a plurality of independent areas.

3. A light-emitting element according to claim 1, wherein the depth of the groove is 2 ~ 4 μm.

4. A light-emitting element according to claim 1, wherein the ratio of the horizontal area of the groove to the horizontal area of the light-emitting surface is 5 ~ 95%.

5. The light-emitting element according to claim 1, wherein: the width of the top opening of the groove is larger than or equal to the depth of the groove.

6. The light-emitting element according to claim 1, wherein the non-groove regions between adjacent grooves have a width W2, W1+ W2 is between 8 ~ 15 μm.

7. The semiconductor light-emitting element according to claim 1, wherein: the inner side wall of the groove deviates from the thickness stacking direction of the semiconductor light-emitting sequence by an angle defined as an inclination (alpha), and the inclination is smaller than 90 degrees.

8. The semiconductor light emitting element as claimed in claim 7, wherein the inclination (α) of the inner wall of the groove is 30 ~ 70 °.

9. The semiconductor light-emitting element according to claim 7, wherein: the depth of the groove is greater than or equal to the thickness from the bottom of the groove to the light-emitting layer.

10. The semiconductor light-emitting element according to claim 1, wherein: and at least routing electrodes and/or electrode expansion strips are arranged in the light blocking area on the light emergent surface side.

11. The semiconductor light-emitting element according to claim 1, wherein: the light transmission blocking area is a light reflection layer covering area or a light absorption layer covering area.

12. The semiconductor light-emitting element according to claim 1, wherein: the groove is one of a conical table groove, a pointed conical groove or an arc-shaped groove.

13. The semiconductor light-emitting element according to claim 1, wherein: a light transmissive barrier is included around the sidewalls of the semiconductor light emitting sequence.

14. The semiconductor light-emitting element according to claim 1, wherein: the light transmission blocking area is an electrode layer covering area.

15. The semiconductor light-emitting element according to claim 1, wherein: the light emitting area of the light emitting surface is only concentrated in the groove.

16. The semiconductor light-emitting element according to claim 1, wherein: the light transmission blocking area on the light emitting surface comprises an electrode covering area and an additional light transmission blocking layer covering area, and the electrode and the additional light transmission blocking layer are electrically insulated.

17. The semiconductor light-emitting element according to claim 16, wherein: the additional light transmission barrier layer is a metal or insulating dielectric layer.

18. The semiconductor light-emitting element according to claim 13, wherein: when the light transmission barrier layer covered around the side wall of the semiconductor light-emitting sequence is a metal layer, a current barrier layer is arranged between the metal layer and the side wall of the semiconductor light-emitting sequence.

Technical Field

The present invention relates to a light emitting device, and more particularly, to a semiconductor light emitting device with concentrated light emitting directions.

Background

Semiconductor light emitting elements are widely used as solid state light emitting elements and widely applied to the fields of illumination, display, communication, electric appliances and the like.

In some application requirements, it is necessary to limit the light emitting direction to be consistent and concentrated, for example, a laser diode-like design needs a small light spot. However, in the current laser diode, the light emitting direction is usually concentrated on a local region on one surface side of the semiconductor light emitting epitaxial stack, and the surface side is usually roughened to increase the light emitting efficiency, but the surface pattern obtained after roughening treatment is irregular, which causes disorder of the light emitting direction, non-concentrated light emitting angle, and insufficient light emitting intensity.

Disclosure of Invention

The semiconductor light-emitting element is characterized in that the light-emitting surface comprises a plurality of grooves, the bottoms of the grooves are positioned in the second conduction type semiconductor layer, the area of the light-emitting surface outside the grooves is a light transmission blocking area, the grooves are in a regular pattern, and the side walls of the grooves are inclined relative to the thickness stacking direction of the semiconductor light-emitting sequence.

Preferably, the grooves are a plurality of separate areas.

Preferably, the depth of the grooves is 2 ~ 4 microns.

Preferably, the horizontal area of the groove accounts for 5 ~ 95% of the horizontal area of the light-emitting surface.

Preferably, the width of the top opening of the groove is greater than or equal to the depth of the groove.

Preferably, the width of the non-groove region between adjacent grooves is W2, and W1+ W2 is between 8 ~ 15 microns.

Preferably, the angle of the inner sidewall main region of the recess deviating from the thickness stacking direction of the light emitting semiconductor sequence is defined as an inclination (α) which is less than 90 °.

Preferably, the inclination (α) of said grooves is 30 ~ 70 °.

Preferably, the light blocking area on the light emergent surface side is at least provided with routing electrodes and/or electrode expansion strips.

Preferably, the light transmission blocking area is a light reflection layer covering area or a light absorption layer covering area.

Preferably, the main area of the inner side wall of the groove comprises a plurality of microstructures, and the size of each microstructure is less than or equal to 1 micron.

Preferably, the regular pattern is an inverted cone-shaped platform, an inverted pointed cone-shaped or an arc-shaped.

Preferably, a light-transmitting barrier is included around a major region of the outer sidewall of the semiconductor light emitting sequence.

Preferably, the light transmission blocking region is an electrode layer covering region.

Preferably, the light emitting area of the light emitting surface is only concentrated in the groove.

Preferably, the light transmission blocking area on the light emitting surface includes an electrode covering area and an additional light transmission blocking layer covering area, and the electrode and the additional light transmission blocking layer are electrically insulated.

Preferably, the light transmission barrier layer is a metal or insulating medium layer.

Preferably, when the light transmission blocking layer covering the main region of the sidewall of the semiconductor light emitting sequence is a metal layer, a current blocking layer is arranged between the metal layer and the main region of the inner sidewall of the semiconductor light emitting sequence.

Through the design, the invention can obtain the following beneficial effects:

the light emitting surface is designed into a groove with inclined side walls, the light emitting direction is more inclined to the direction vertical to the horizontal surface of the semiconductor light emitting sequence to be concentrated, the technical effect of concentrating the light emitting angle is achieved, the application requirement of a point light source is met, the light emitting area is not required to be limited in the local area of the light emitting surface, and the light intensity can be increased.

Drawings

Fig. 1 is a schematic cross-sectional view of a light-emitting device according to the present invention along a stacking direction of semiconductor light-emitting sequences according to an embodiment.

Fig. 2 is a partially enlarged view of the oval area of the light emitting element shown in fig. 1.

Fig. 3 is a schematic plan view of a light emitting surface of a light emitting element according to an embodiment of the invention.

Fig. 4 is a schematic cross-sectional view along the stacking direction of the semiconductor light emitting sequence at the position of the dotted line in fig. 3.

Fig. 5 is a schematic plan view of a light emitting surface of another light emitting device according to the present invention in an embodiment.

Fig. 6 and 7 are schematic cross-sectional views of the semiconductor light emitting sequence in fig. 5 taken along the stacking direction of the semiconductor light emitting sequence at the positions of the dotted line in the X direction and the dotted line in the Y direction, respectively.

Fig. 8 is a schematic cross-sectional view of a light emitting device of the present invention along the stacking direction of semiconductor light emitting sequences according to the embodiment mentioned in the embodiment, wherein the main area of the inner sidewall of the light emitting device is covered by a light transmission blocking layer.

Fig. 9 is a schematic sectional view of a light-emitting element of the present invention mentioned in the embodiment, the light-emitting element including a reflective layer, a bonding layer, a permanent support substrate, and a first electrode on a non-light-exit surface side, along a stacking direction of a semiconductor light-emitting sequence.

Description of reference numerals:

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

In the following embodiments of the present invention, words indicating orientations, such as "upper", "lower", "left", "right", "horizontal", "peripheral", etc., are referred to only for the purpose of better understanding of the present invention by those skilled in the art, and should not be construed as limiting the present invention.

The conventional light-emitting element at least comprises a semiconductor light-emitting sequence, wherein the semiconductor light-emitting sequence comprises a first type semiconductor layer, a second type semiconductor layer and a light-emitting layer, and the light-emitting layer is positioned between the first type semiconductor layer and the second type semiconductor layer, the first type semiconductor layer and the second type semiconductor layer provide electrons and holes, and the electrons and the holes are compounded in the light-emitting layer under the drive of current to emit light.

Therefore, the present embodiment makes the following improvements on the basis of the conventional structure, and the technical effects of deflecting the light emitting direction to the direction perpendicular to the horizontal light emitting surface of the semiconductor light emitting sequence and concentrating the light emitting angle are achieved by the ordered grooves designed on the light emitting surface, so as to meet the requirement of concentrating the light beam direction of the point light source, and the light emitting area does not need to be limited in the local area of the light emitting surface, so that the light intensity can be increased.

As shown in fig. 1 ~ 2, the present embodiment provides a light emitting device 100 comprising a semiconductor light emitting sequence including a first type semiconductor layer 101, a second type semiconductor layer 103, and a light emitting layer 102 disposed between the first type semiconductor layer 101 and the second type semiconductor layer 103.

The material of the semiconductor light emitting sequence comprises a group III-V semiconductor material, such as AlxInyGa (1-x-y) N or AlxInyGa (1-x-y) P or AlxGa1-xAs, wherein 0 ≦ x, y ≦ 1; (x + y) is less than or equal to 1. Depending on the material of the light-emitting layer 102, the semiconductor light-emitting sequence can emit infrared light with a wavelength above 650nm, red light between 610nm and 650nm, green light between 530nm and 570nm, or blue light between 420nm and 490 nm.

In this embodiment, the red light epitaxy between 610 ~ 650nm is taken as an example, wherein the first type semiconductor layer 101 and the second type semiconductor layer 103 of the semiconductor light emitting sequence respectively include an N-type cladding layer and a P-type cladding layer for providing electrons or holes, which may be aluminum indium phosphide, and the second conductivity type semiconductor layer 103 further includes a window layer of aluminum gallium indium phosphide for current spreading and for providing a light emitting surface, and the thickness of the window layer is preferably 3 ~ 6 μm.

As shown in fig. 3, based on a normal parallel to the thickness direction of the semiconductor light emitting sequence, the inner sidewall of the groove 105 has an angle deviating from the normal, the angle being defined as an inclination angle, the inclination angle being less than 90 degrees, the preferred inclination angle being between 30 ~ 70 degrees, and more preferred being that the inclination of at least a main region of the inner sidewall of the groove is 40 ~ 60 degrees.

The grooves may be formed by the following process: a mask pattern is formed on the surface of the second conductive type semiconductor layer by a photoresist patterning process, and then the exposed surface of the mask pattern of the second conductive type semiconductor layer 103 is dry-etched or wet-etched.

The bottom of the groove 105 is located in the second conductive type semiconductor layer 103, and thus the thickness of the second conductive type semiconductor layer 103 needs to be designed to be greater than the depth of the groove 105, more specifically, the bottom of the groove is located in the window layer of the second conductive type semiconductor layer.

The depth D1 of the groove 105 is preferably equal to or greater than the thickness from the bottom of the groove to the light-emitting layer (including the thickness of part of the window layer and the cladding layer), preferably more than two times and less than five times the thickness of the former, the depth W1 of the groove is preferably 2 ~ 4 micrometers, or preferably 3 ~ 4 micrometers, and the thickness of the window layer at the bottom of the groove is preferably 1 ~ 2 micrometers to facilitate current spreading.

The width W1 of the top opening of the groove 105 is greater than or equal to D1, more preferably, W1 is 3 ~ 4 microns, which is favorable for light extraction, preferably, the groove 105 can cover the surface of the light extraction surface as completely as possible, and the horizontal coverage area of the groove 105 on the surface of the second-type semiconductor layer 104 is 5 ~ 95%, or preferably 30 ~ 60%.

The non-groove regions between the grooves 105 have a width W2, W1+ W2 is between 8 ~ 15 microns, and the minimum width of W1+ W2 is 8 microns but cannot exceed 15 microns, due to the limitations of the current photoresist patterning process.

The region outside the groove 105 is a light transmission blocking region, the light transmission blocking region comprises a region with the width of W2 between grooves, the light transmission blocking region is a region covered by the light transmission blocking layer 104, the inner side wall and the bottom of the groove are exposed, and the effect that when light emitted by the light emitting layer reaches the surface of the light transmission blocking layer 104, the light can be blocked and transmitted can be realized, so that most of the light emitted by the light emitting layer is emitted through the inner side wall of the groove, the light emitting direction is more deviated to the horizontal light emitting surface of the vertical semiconductor light emitting sequence, the technical effect of concentrating the light emitting angle is achieved, the application requirement of a point light source is met, the light emitting region does not need to be limited in the local region of the. On the contrary, if the surface of the light-emitting surface outside the grooves is not covered by the light transmission blocking region layer, light can exit from the inside of the grooves and the areas between the grooves, the light-emitting direction is still mostly scattered due to the areas between the grooves, and the width of the bottom of the groove preferably occupies less than 20% or less than 10% of the width of the opening of the groove to increase the light-emitting area of the side wall. The sum of the horizontal coverage area ratio of the light-transmission blocking layer 104 and the horizontal coverage area ratio of the groove 105 is equal to the horizontal sectional area of the second conductive type semiconductor layer 103.

Preferably, the light transmission blocking layer 104 is a layer for realizing light transmission blocking, preferably having a light absorption effect and/or a reflection effect, and specifically may be a metal material or an insulating material, the insulating material is an inorganic dielectric film or an organic polymer film, the metal material may be a light absorption material, and contains titanium, chromium, nickel, or a combination thereof, the thickness is preferably more than 30nm, so as to ensure that the metal material has a light absorption effect, and the absorbance is at least 80%. The metal material may also be a reflective material, such as aluminum, gold, silver, zinc, nickel, beryllium or germanium, or a combination thereof, and is thick enough to allow the layer to reflect light emitted by the light-emitting layer, and the reflective layer has a reflectivity of at least 80%.

The light-transmission blocking layer 104 may include an electrode layer, the bottom of which is in contact with the second conductive type semiconductor layer directly or through an ohmic contact layer.

As an embodiment, as shown in fig. 3 ~ 4, the light transmission blocking layer 104 is an electrode layer, that is, the light transmission blocking regions between adjacent grooves are electrode layer covered regions, the electrode layer horizontally diffuses current from the wire electrode 1041 on the light emitting surface side in a manner of surrounding a plurality of grooves, and longitudinally transfers current between the electrode layer and the second conductive type semiconductor layer 103, the light transmission blocking layer 104 forms the second electrode 112, an ohmic contact layer 1031, which is a part of the second conductive type semiconductor layer, and more preferably a local highly doped layer, is also included between the electrode layer and the second conductive type semiconductor layer, so as to facilitate ohmic contact between the electrode layer and the second conductive type semiconductor layer.

The routing electrodes 1041 are located on the light-emitting surface, preferably in a non-central region of the light-emitting surface, that is, in an edge region of the light-emitting surface or a corner region of the light-emitting surface, and through this design, the electrode routing regions are separated from the light-emitting regions of the grooves to form independent light-emitting regions and routing regions, so as to prevent the routing electrodes 1041 from blocking light to the light-emitting regions to form a light shadow region.

Or as an alternative embodiment, as shown in fig. 5 ~ 7, the light transmission blocking region is divided into two regions, namely an electrode layer covering region and a non-electrode layer covering region, to form regions with different functions, and the non-electrode layer covering region and the electrode layer covering region are electrically insulated from each other, the electrode layer covering region includes at least one wire bonding electrode 1041 for external electrical connection, the wire bonding electrode 1041 further includes a current spreading bar 1042 around the wire bonding electrode 1041, the current spreading bar 1042 horizontally extends from the wire bonding electrode 1041 on the light-emitting surface, and the current spreading bar 1042 extends to the surface side of the second conductive type semiconductor layer between partial grooves, so that current can be horizontally spread from the wire bonding electrode to the spreading bar and then longitudinally transferred to the surface of the second conductive type semiconductor layer to realize uniform spreading of current, and light is uniformly emitted from the light-emitting surface.

The width of the current spreading bar is preferably between 1 ~ 3 microns the shape of the current spreading bar can be circular, linear such as curved or straight or a combination of circular and linear.

The electrode layer, the wire bonding electrode and the current spreading bar have at least the light transmission blocking effect on the light radiated by the light emitting layer, and can have a light absorbing layer, or more preferably, the bottom layer of the electrode layer, the wire bonding electrode or the current spreading bar is a light reflecting layer. The electrode layer, the routing electrode and the current spreading strip are preferably formed by combining a plurality of layers of metals or alloys, and the metals comprise at least one of the following metals: copper, aluminum, gold, lanthanum, or silver; the metal alloy comprises at least one of: germanium gold, beryllium gold, chromium gold, silver titanium, copper tin, copper zinc, copper cadmium, tin lead antimony, tin lead zinc, nickel tin, or nickel cobalt.

As shown in FIG. 5 ~ 7, the covering material of the non-electrode layer covering region is different from the electrode layer covering region, and the covering material of the non-electrode layer covering region is mainly used for light transmission blocking, and preferably has a stronger light transmission blocking function than the electrode covering region, i.e. includes at least one additional light transmission blocking layer 1043, and is electrically insulated from the electrode layer covering region, the additional light transmission blocking layer 1043 can be a light reflection layer or a light absorption layer, and reflects the light beam back to the light emitting layer, and emits light from the main region of the inner sidewall of the groove or absorbs the light blocking to transmit light.

Since the non-electrode layer covered region is electrically insulated from the electrode layer covered region, the additional light transmission blocking layer 1043 may be a metal, a light absorbing metal or a reflective metal, and as shown in fig. 8, an insulating medium layer 106 is further included between the light transmission blocking layer 1043 and the second conductive type semiconductor layer. The reflective metal and the insulating dielectric layer 106 are configured as an ODR structure to increase the reflective effect. The insulating dielectric layer 106 is preferably made of at least one material with low refractive index, such as silicon oxide, silicon nitride, magnesium fluoride, and the like. Or when the light transmission blocking layer 1043 is an inorganic dielectric layer, the light transmission blocking layer 104 is preferably a bragg reflection layer, such as a titanium oxide/silicon oxide repeated stack layer.

As an embodiment, as shown in fig. 9, the sidewalls of the semiconductor light emitting sequence are also designed as light transmission blocking regions, that is, a light transmission blocking layer 1044 is included and covers around the sidewalls, and at least the main area of the sidewalls of the light emitting layer 102 is covered by the light transmission blocking layer, so that the light emitted from the light emitting layer is blocked from being transmitted out from the sidewalls, thereby the light is concentrated in the grooves on the light emitting surface and emitted out to concentrate the light emitting angle.

The material of the light transmission blocking layer 1044 of the sidewall of the semiconductor light emitting sequence may be a light absorbing material and or a reflective material. The light transmission blocking layer 1044 on the sidewall may be continuous or discontinuous with the light transmission blocking layer 104 on the light exit surface, and may be made of the same material or different materials, or further, the light transmission blocking layer 104 extends from the light exit surface side to cover the portion of the sidewall where the light transmission blocking layer 1044 is formed.

As shown in fig. 9, when the light-transmitting barrier layer 1044 on the sidewall of the semiconductor light-emitting sequence is a metal layer, another insulating protection layer 107 is further included between the light-transmitting barrier layer 1044 and the sidewall for electrically insulating the light-transmitting barrier layer 1044 from the semiconductor light-emitting sequence. Or the insulating protection layer 107 may be the same layer as the insulating dielectric layer 106 shown in fig. 8. The insulating protective layer 107 is preferably made of at least one material with a low refractive index, such as silicon oxide, silicon nitride, or magnesium fluoride.

As shown in fig. 9, the semiconductor light emitting sequence has a first electrode 111 electrically connected to the first conductive type semiconductor layer 101 on the non-light emitting surface side.

The first electrode 111 is led out from the non-light-emitting side of the semiconductor light-emitting sequence, and the non-light-emitting side can have a permanent supporting substrate 110, which is a conductive substrate, such as a silicon, metal-based substrate, such as a copper-tungsten substrate or a gallium arsenide-based substrate. The permanent support substrate 110 may be a growth substrate for a semiconductor light emitting sequence, or the semiconductor light emitting sequence may be transferred onto the permanent support substrate 110 through the bonding layer 109 after the semiconductor light emitting sequence is obtained on the growth substrate. The first electrode 111 is located on the back side of the permanent support substrate 110, and the first electrode 111 includes, but is not limited to, a metal layer such as gold, gold tin, etc.

The bonding layer 109 and the first conductivity type semiconductor layer 101 may further include a reflective layer 108 therebetween, and the reflective layer 108 is configured to reflect light emitted from the light emitting layer 103 to the non-light-emitting surface side back to the semiconductor light emitting sequence as much as possible and emit light from the light-emitting surface. The reflective layer 108 has a reflectivity of at least 80%, for example a metallic reflective layer, such as gold or silver, or for example a bragg reflective layer, such as a DBR reflective layer made of a semiconductor material of the first conductivity type or a bragg reflective layer made of an inorganic insulating material, such as silicon oxide/titanium oxide, or for example an ODR reflective layer, such as gold and silicon oxide, combined with a dielectric insulating layer. The coverage area of the reflective layer 108 on the non-light-emitting surface of the semiconductor light-emitting sequence is at least greater than or equal to the coverage area of the groove, or more preferably, the reflective layer 108 covers the whole non-light-emitting surface of the semiconductor light-emitting sequence.

The light-emitting element can be used as a similar laser diode and is widely applied to the fields of sensors and communication.

While the drawings and description above correspond to particular embodiments, respectively, it should be understood that elements, embodiments, design criteria and technical principles described or disclosed in the various embodiments may be arbitrarily referenced, exchanged, matched, coordinated or combined as required, unless they conflict or conflict with each other or are difficult to implement together.

Although the invention has been described with reference to specific embodiments, it is not intended to limit the scope, sequence, or use of the materials or methods. Various modifications and alterations of this invention can be made without departing from the spirit and scope of this invention.