CN201307601Y - Filled type inverted trapezoidal microstructure high-brightness light-emitting diode - Google Patents

Abstract

The utility model discloses a filling type inverted trapezoid microstructure high-brightness light-emitting diode, which comprises a permanent substrate and an epitaxial wafer, wherein a dielectric layer is deposited on the conical wall of an inverted cone frustum hole etched on the epitaxial wafer which is arranged right above and on the surface of the epitaxial wafer, a metal layer is deposited on the surfaces of the dielectric layer and the epitaxial wafer, a barrier layer is deposited on the metal layer, and a metal filling layer is deposited in the space of the inner wall of the barrier layer by metal sputtering; the epitaxial wafer is inverted and connected with the permanent substrate in a vacuum bonding way; and depositing a metal electrode on the permanent substrate, and depositing an ohmic contact electrode on the top of the epitaxial wafer. The utility model discloses metal sputtering is filled up in the space of barrier layer inner wall has the metal filling layer, realizes the seamless plane bonding of epitaxial wafer and permanent substrate, has solved the poor problem of epitaxial wafer and permanent substrate bonding force to and there is the crack problem easily to lead to epitaxial wafer and permanent substrate bonding process in the inverted cone frustum hole that etches out in the epitaxial wafer.

Description

A Filled Inverted Trapezoidal Microstructure High Brightness Light Emitting Diode

technical field

The utility model relates to an LED light-emitting diode, in particular to a filling-type inverted trapezoidal microstructure high-brightness light-emitting diode.

Background technique

Light Emitting Diode (LED) is a cold light source, which is widely used because of its small size, long life, low driving voltage, fast response rate, and excellent shock resistance. However, traditional diodes have relatively low luminous efficiency. For example, take aluminum gallium indium phosphide (AlGaInP) light-emitting diodes as an example, aluminum gallium indium phosphide is a four-element compound semiconductor material, which is grown on a lattice-matched gallium arsenide (GaAs) substrate for manufacturing high brightness Red, orange, yellow, and yellow-green light-emitting diodes have high luminous efficiency. However, because the gallium arsenide substrate is a light-absorbing substrate, it will absorb the visible light emitted by aluminum gallium indium phosphide, and its thermal conductivity is poor. Therefore, its luminous efficiency in high current operation is limited.

Therefore, in order to improve the luminous efficiency of light-emitting diodes, it is necessary to extract most of the photons propagating downward and the photons reflected back to the interior of the semiconductor material to reduce the absorption of the GaAs substrate. Bragg reflectors (Distributed BraggReflectors, DBRs) are grown between them to reflect the light from the back to the surface of the chip. FIG. 1 is a schematic cross-sectional structure diagram of an existing AlGaInP multi-quantum well (MQW) light-emitting diode 200 with high reflectivity DBRs. This AlGaInP multi-quantum well (MQW) light-emitting diode structure includes n-GaAs substrate 201, n-GaAs buffer layer 202, DBRs structure layer 203, n-AlInP lower confinement layer (n-cladding layer) 204, non-doped ( Al _0.15 Ga _0.85 ) _0.5 In _0.5 P multiple quantum well (MQW) active region 205, p-AlInP upper confinement layer (p-cladding layer) 206, p-type current spreading layer 207, p-type ohmic contact layer 208, bottom plane Metal contacts 210 and upper surface electrodes 209 . That is, on the basis of the structure in Figure 1, a DBRs structure is grown between the GaAs substrate and the active region, and a current expansion layer (window layer) is grown under the p-type ohmic contact layer to effectively expand the current. However, because the reflectivity angular bandwidth of the actual DBRs mirror is limited, the reflectivity is only large for the light incident near the normal direction, and the light reflectivity outside this range drops sharply, so it cannot effectively reflect the light propagating to the GaAs substrate. A considerable portion of the light is still absorbed by the GaAs substrate.

Utility model content

In order to solve the problem of luminous efficiency of the above-mentioned light-emitting diodes, the utility model aims to propose a high-brightness light-emitting diode with a filled inverted trapezoidal microstructure.

The technical scheme adopted by the utility model to solve the above problems is: a filled-type inverted trapezoidal microstructure high-brightness light-emitting diode, including a permanent substrate and an epitaxial wafer, which is characterized in that: the inverted epitaxial wafer etched on the upright A dielectric layer is deposited on the conical wall of the conical frustum hole and the surface of the epitaxial wafer, a metal layer is deposited on the dielectric layer and the surface of the epitaxial wafer, a barrier layer is deposited on the metal layer, and metal sputtering is deposited in the space of the inner wall of the barrier layer. There is a metal filling layer; the epitaxial wafer is inverted and connected to the permanent substrate by vacuum bonding; metal electrodes are deposited on the permanent substrate, and ohmic contact electrodes are deposited on the top of the epitaxial wafer.

In the utility model, a layer of sticking layer is pasted on the substrate substrate of the layered structure, and a metal solder layer is deposited and connected on the sticking layer to form a permanent substrate of a laminated structure; , the first conductivity type current spreading layer, the first conductivity type lower confinement layer, the non-doped active region, the second conductivity type upper confinement layer, the second conductivity type current spreading layer and the second conductivity type ohmic contact layer are stacked and connected Composition; the cross-section of the metal filling layer is an inverted trapezoid.

The beneficial effects of the utility model are: the utility model is filled with a metal filling layer by metal sputtering in the space of the inner wall of the barrier layer, realizing the seamless plane bonding of the epitaxial wafer and the permanent substrate, and solving the problem of the connection between the epitaxial wafer and the permanent substrate. The problem of poor bonding force of the substrate and the existence of gaps in the inverted frustum hole etched during epitaxy can easily cause cracks in the bonding process between the epitaxial wafer and the permanent substrate.

Description of drawings

Fig. 1 is the schematic cross-sectional structure schematic diagram of the existing AlGaInP multi-quantum well (MQW) light-emitting diode with high reflectivity DBRs;

Fig. 2 is the sectional view of layered structure of the present utility model;

In Fig. 2: 304. The ohmic contact layer of the first conductivity type; 305. The current spreading layer of the first conductivity type;

                306. The first conductivity type lower confinement layer;     307. The non-doped active region;

            308. The upper confinement layer of the second conductivity type; 309. The current spreading layer of the second conductivity type;

                                                                              .

402. Paste layer; 403. Metal solder layer;

501. Dielectric layer; 502. Metal layer;

503. Barrier layer; 504. Metal filling layer;

505. Metal electrodes; 506. Ohmic contact electrodes.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

As shown in FIG. 2, a filled inverted trapezoidal microstructure high-brightness light-emitting diode uses MOCVD epitaxial growth technology to grow a light-emitting diode epitaxial wafer on a GaAs substrate, which sequentially includes a first conductivity type ohmic contact layer 304, a first conductivity type The current spreading layer 305, the lower confinement layer 306 of the first conductivity type, the non-doped active region 307, the upper confinement layer 308 of the second conductivity type, the current spreading layer 309 of the second conductivity type, and the ohmic contact layer 310 of the second conductivity type Cascading connection composition. A dielectric layer is deposited on the cone wall of the inverted frustum hole etched on the upright epitaxial wafer and on the surface of the epitaxial wafer, that is, a photomask is made on the second conductivity type ohmic contact layer 310 of the light-emitting diode epitaxial wafer, and a dry method is used. Etching the second conductivity type ohmic contact layer 310 and the second conductivity type current spreading layer 309, and then wet etching the second conductivity type upper confinement layer 308, the non-doped active region 307 and the first conductivity type lower confinement layer 306, Then a dielectric layer 501 is deposited on the epitaxial wafer, and the dielectric layer in the center of the second conductivity type ohmic contact layer 310 is etched away by a wet method; a metal layer 502 is deposited on the dielectric layer 501 and the surface of the epitaxial wafer, and the metal layer 502 and the dielectric layer are combined as a light reflection A barrier layer 503 is deposited on the metal layer 502 for blocking the interdiffusion between the metal solder layer and the metal layer 502; evaporation or sputtering of the metal filling layer 504 completes the fabrication of the epitaxial wafer with a mirror.

The permanent substrate is composed of a substrate substrate 401, an adhesive layer 402, and a metal solder layer 403 laminated and connected. A metal solder layer 403 forms the permanent substrate of the stacked structure.

The above-mentioned epitaxial wafers with reflective mirrors are stacked on the metal solder layer 403 of the permanent substrate in a flip-chip manner, and bonded under vacuum; metal is deposited on the base substrate 401 at the bottom of the permanent substrate The electrode 505 is deposited on the first conductive type ohmic contact layer 304 of the light emitting diode epitaxial wafer 300, and the patterned electrode 506 is deposited, and the first conductive type ohmic contact layer 304 is wet etched with the above patterned electrode 506 as a mask, and formed by etching the mesa and cutting The utility model.

Claims (3)

1. A filling-type inverted trapezoidal microstructure high-brightness light-emitting diode, containing a permanent substrate and an epitaxial wafer, characterized in that: on the cone wall of the inverted conical frustum hole etched out on the upright epitaxial wafer and on the surface of the epitaxial wafer A dielectric layer is deposited, a metal layer is deposited on the surface of the dielectric layer and the epitaxial wafer, a barrier layer is deposited on the metal layer, and a metal filling layer is deposited in the space of the inner wall of the barrier layer by metal sputtering; the epitaxial wafer is inverted and the permanent lining Bottom vacuum bonding connection; metal electrodes are deposited on the permanent substrate, and ohmic contact electrodes are deposited on the top of the epitaxial wafer. 2. A kind of filling type inverted trapezoidal microstructure high-brightness light-emitting diode as claimed in claim 1, is characterized in that: on the base plate substrate of layered structure sticks one deck sticking layer, deposits and connects one on the sticking layer The metal solder layer constitutes the permanent substrate of the stacked structure; the epitaxial wafer is sequentially composed of the first conductivity type ohmic contact layer, the first conductivity type current spreading layer, the first conductivity type lower confinement layer, the non-doped active region, the second The conductive type upper confinement layer, the second conductive type current spreading layer and the second conductive type ohmic contact layer are stacked and connected. 3. A high-brightness light-emitting diode with a filled inverted trapezoidal microstructure as claimed in claim 1, characterized in that: the cross-section of the metal filled layer is inverted trapezoidal.

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