CN114744092A - Manufacturing method and manufacturing machine of micro light-emitting diodes with reduced non-radiative recombination - Google Patents

Abstract

The present invention provides a method for manufacturing micro-LEDs with reduced non-radiative recombination, and provides an etched LED epiwafer, wherein the etched LED epiwafer includes a plurality of etched grooves and a plurality of In the platform structure, an etched sidewall of the platform structure includes a stack of a first-type semiconductor layer, an active layer and a second-type semiconductor layer. Two-stage atomic layer deposition is performed on the etched light-emitting diode epiwafer, wherein the temperature ranges of the two-stage atomic layer deposition are different. The first atomic layer deposition is used to repair dangling bonds and defects on the etched sidewalls of the mesa structure, and the second atomic layer deposition is used to form a passivation layer on the etched sidewalls of the mesa structure. The manufacturing method of the present invention can reduce the non-radiative recombination of the micro light emitting diode, and can effectively improve the luminous brightness and luminous efficiency of the micro light emitting diode.

Description

Manufacturing method and manufacturing machine of micro light-emitting diodes with reduced non-radiative recombination

technical field

The invention relates to a manufacturing method and a manufacturing machine of a micro-light-emitting diode that reduces non-radiative recombination, which can reduce the non-radiative recombination of the micro-light-emitting diode, and can effectively improve the luminous brightness and luminescence of the micro-light-emitting diode. efficiency.

Background technique

Light-emitting diodes have the advantages of high conversion efficiency, long service life, small size and high safety, and have become a new generation of lighting sources. In addition, light emitting diodes also replace traditional cold cathode tubes as the backlight source of display panels, and are especially suitable for small portable electronic devices, such as notebook computers, mobile phones and tablet computers.

Liquid crystal displays are not self-luminous, and suffer from poor efficiency. Even if the liquid crystal display displays white, less than 10% of the light emitted by the backlight usually passes through the panel, increasing the power consumption of portable electronic devices. In addition to the backlight, the liquid crystal display also needs to be equipped with devices such as polarizers, liquid crystals, and color filters, so that the size of the liquid crystal display cannot be further reduced.

In contrast, organic light-emitting diodes have the advantages of self-luminescence, wide viewing angle, high contrast, low power consumption, high response rate and flexibility, and have gradually replaced liquid crystal displays as the display of a new generation of portable electronic devices. . However, organic light-emitting diodes still have problems such as branding, short lifespan, color fade, and PWM dimming, and major manufacturers have begun to develop next-generation display panels.

At present, Micro LED Display (Micro LED Display) is likely to become the next-generation display panel. Like organic light-emitting diode displays, micro-LED displays are self-luminous, and have the advantages of high color saturation, short response time, and long service life.

At present, there are still many cost and technical bottlenecks to be overcome in the commercialization of micro-LEDs. In the manufacturing process of light-emitting diodes, epitaxial materials are grown on a sapphire substrate mainly by metal-organic chemical vapor deposition (MOCVD) to form light-emitting diode epitaxial wafers. The LED epiwafer is etched, and a plurality of etching trenches and a plurality of mesa structures (MESA) are formed on the surface of the LED epiwafer. Then, the light-emitting diode epiwafer is cut along the etched trench to complete the fabrication of light-emitting diode crystal grains.

In the process of etching LED epiwafers, defects and dangling bonds will be formed on the etched sidewalls of the platform structure, resulting in non-radiative recombination of the etched sidewalls of the LEDs. recombination), thereby affecting the luminous brightness of the light-emitting diode.

The size of the traditional light-emitting diode and platform structure is much larger than that of the etched sidewall, so the non-radiative recombination has little effect on the overall luminous brightness and can usually be ignored. However, the size of the micro-LED and the mesa structure is small, so that the non-radiative recombination that occurs in the etched sidewall will have a considerable impact on the luminous brightness of the micro-LED. Therefore, how to reduce the non-radiative recombination of the etched sidewalls of the micro-LEDs has become a major problem that must be faced during the commercialization of the micro-LEDs.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems of the prior art, the present invention proposes a method for manufacturing a micro-LED with reduced non-radiative recombination, which can effectively repair the defects and overhangs on the etched sidewall of the micro-LED and mesa structure (MESA). A dangling bond is formed, and a passivation layer is formed on the micro-LED and the mesa structure to reduce non-radiative recombination on the etched sidewalls of the micro-LED.

An object of the present invention is to provide a method for manufacturing a micro-LED with reduced non-radiative recombination, which is mainly used for processing etched LED epiwafers. The light-emitting diode epitaxy wafer includes a substrate, a first-type semiconductor layer, an active layer and a second-type semiconductor layer, wherein the first-type semiconductor layer, the active layer and the second-type semiconductor layer are arranged on the substrate in a stacked manner superior. A plurality of etching trenches and a plurality of mesa structures are formed on the surface of the etched LED epiwafer, wherein the etched sidewalls of the mesa structures include exposed first-type semiconductor layers, active layers and second-type semiconductor layers. The LED epiwafer can then be cut along the etched trenches to produce a plurality of micro LEDs.

During the etching process, at least one floating bond and/or at least one defect will be formed on the etched sidewalls of the LED epiwafer, and non-radiative recombination will be generated on the etched sidewalls of the micro-LED and mesa structures. The size of the micro-LED is very small, usually between 10-100um, so that the size of the micro-LED and platform structure is similar to that of the etched sidewall. Therefore, when the etched sidewall produces non-radiative recombination, the luminous brightness of the micro-LED will be greatly affected. To this end, the present invention proposes a method for manufacturing a micro-LED with reduced non-radiative recombination, which mainly repairs suspending bonds and/or defects on the etched LED epiwafer, and then repairs the repaired LED. Atomic layer deposition is performed on the electrode epitaxy wafer to form a passivation layer on the etched sidewall of the LED epitaxy wafer to prevent non-radiative recombination on the etched sidewall of the micro-LED and platform structure, and can Effectively improve the luminous brightness and conversion efficiency of micro-LEDs

An object of the present invention is to provide a method for manufacturing a micro-LED with reduced non-radiative recombination, which mainly involves two-stage atomic layer deposition on at least one etched LED epiwafer, wherein the two-stage atomic layer is deposited in two stages. The temperature of layer deposition varies. The first atomic layer deposition is performed on the etched light-emitting diode epiwafer, so that the dangling bonds and/or defects of the etched sidewall can be repaired. The second atomic layer deposition is performed on the etched LED epiwafer after the first atomic layer deposition, and a passivation layer is formed on the etched sidewall of the LED epiwafer to prevent micro-LED Non-radiative recombination occurs on the etched side walls of the volume and platform structures.

An object of the present invention is to provide a method for manufacturing micro-LEDs with reduced non-radiative recombination, mainly placing the etched LED epiwafers in a reaction chamber, and delivering a repair gas to the The reaction chamber, wherein the repairing gas reacts with the dangling bonds and/or defects of the etched sidewall, and repairs the dangling bonds and/or defects of the etched LED epiwafer. Then, atomic layer deposition is performed on the repaired LED epiwafer to form a passivation layer on the etched sidewalls of the mesa structure.

In addition, according to the type of the repairing gas, it can be determined whether to provide an AC voltage to the AC coil adjacent to the reaction chamber, so that the repairing gas can form a plasma, wherein the plasma-forming repairing gas can improve the repairing of the floating bond of the light-emitting diode. and/or defects, and is beneficial for reducing non-radiative recombination in the etched sidewalls of microLEDs and mesa structures.

In order to achieve the above purpose, the present invention proposes a method for manufacturing a micro-LED with reduced non-radiative recombination, including: providing at least one etched LED epiwafer, the etched LED epiwafer comprising: a plurality of etched trenches and a plurality of platform structures, wherein the platform structure includes a first-type semiconductor layer, an active layer and a second-type semiconductor layer, and the active layer is located between the first-type semiconductor layer and the second-type semiconductor layer; The etched LED epiwafer is subjected to a first atomic layer deposition in a first temperature range; and the etched LED epiwafer subjected to the first atomic layer deposition is subjected to a second temperature range Atomic layer deposition is performed, and a passivation layer is formed on the first type semiconductor layer, the active layer and the second type semiconductor layer on at least one etched sidewall of the mesa structure, wherein the first temperature range is different from the second temperature range.

The present invention provides another method for manufacturing micro-LEDs with reduced non-radiative recombination, comprising: providing at least one etched LED epiwafer, wherein the etched LED epiwafer includes a plurality of etched grooves and a plurality of platform structures, wherein the platform structure includes a first-type semiconductor layer, an active layer and a second-type semiconductor layer, and the active layer is located between the first-type semiconductor layer and the second-type semiconductor layer; The diode epitaxy wafer is placed in a reaction chamber, and a repairing gas is delivered into the reaction chamber, wherein the repairing gas will react with the etched LED epitaxy wafer; and the etched LED epitaxy wafer is treated An atomic layer deposition is performed, and a passivation layer is formed on the first type semiconductor layer, the active layer and the second type semiconductor layer on at least one etched sidewall of the mesa structure.

The present invention also provides a manufacturing machine for reducing non-radiative recombination of micro-LEDs, comprising: a transfer cavity, including at least one transfer device, for transferring at least one etched LED epiwafer, wherein The etched light-emitting diode epiwafer includes a plurality of etched trenches and a plurality of platform structures. The platform structure includes a first-type semiconductor layer, an active layer and a second-type semiconductor layer, and the active layer is located in the first-type semiconductor layer. and between the second type semiconductor layer; at least one first atomic layer deposition chamber is connected to the transfer chamber, wherein the transfer device transfers the etched light-emitting diode epiwafer to the first atomic layer deposition chamber, and in the first atomic layer deposition chamber In an atomic layer deposition chamber, a first atomic layer deposition is performed on the etched LED epiwafer in a first temperature range; and at least one second atomic layer deposition chamber is connected to the transfer chamber, wherein the transfer device will The etched light-emitting diode epitaxy wafer after the first atomic layer deposition is transferred to the second atomic layer deposition chamber, and the etched light-emitting diode epitaxy is performed in the second atomic layer deposition chamber at a second temperature range A second atomic layer deposition is performed on the wafer to form a passivation layer on the first type semiconductor layer, the active layer and the second type semiconductor layer on at least one etched sidewall of the mesa structure, wherein the first temperature range and the second temperature range The interval is different.

The present invention provides another fabrication machine for reducing non-radiative recombination of micro-LEDs, comprising: a transfer cavity including at least one transfer device for transferring at least one etched LED epiwafer, wherein The etched light-emitting diode epiwafer includes a plurality of etched trenches and a plurality of platform structures. The platform structure includes a first-type semiconductor layer, an active layer and a second-type semiconductor layer, and the active layer is located in the first-type semiconductor layer. and between the second type semiconductor layer; at least one reaction chamber is connected to the transfer chamber, wherein the transfer device transfers the etched LED epiwafer to the reaction chamber, and delivers a repairing gas to the reaction chamber, making the repairing gas react with the etched LED epiwafer; and at least one atomic layer deposition chamber connected to the transfer chamber, wherein the transfer device transfers the etched LED epiwafer in the reaction chamber to the atomic layer A deposition chamber, and an atomic layer deposition is performed on the etched light-emitting diode epiwafer in the atomic layer deposition chamber, so as to etch the first-type semiconductor layer, the active layer and the second-type semiconductor layer on at least one sidewall of the platform structure The type semiconductor layer forms a passivation layer.

The method for manufacturing a micro-LED with reduced non-radiative recombination, wherein the first atomic layer is deposited for repairing at least one dangling bond or at least one defect in the etched LED epiwafer, and the second atomic layer A passivation layer is deposited on a top surface of the mesa structure.

The manufacturing method of the reduced non-radiative recombination micro-light emitting diode, wherein a precursor gas used in the first atomic layer deposition, the second atomic layer deposition and the atomic layer deposition includes organometallic compounds, organosilicon compounds, chlorinated Silicon compounds, organoaluminum compounds, water, glycols, ozone or ethanol.

The manufacturing method of the micro-light emitting diode with reduced non-radiative recombination, wherein the atomic layer deposition is carried out in the reaction chamber.

The manufacturing method of the reduced non-radiative recombination micro-light-emitting diode includes providing an AC voltage to an AC coil adjacent to the reaction chamber, so that the repairing gas in the reaction chamber becomes a plasma, wherein the plasma is The repairing gas will react with the etched LED epiwafer, and repair at least one dangling bond or at least one defect of the etched LED epiwafer, and the second atomic layer is deposited on a top surface of the mesa structure Set passivation layer.

In the manufacturing method of the micro-LED with reduced non-radiative recombination, the repairing gas is nitrogen, oxygen or ozone.

The beneficial effects of the present invention are: the defects and dangling bonds on the etched sidewalls of the micro-LED and the platform structure can be effectively repaired, and a passivation layer can be formed on the micro-LED and the platform structure, so as to reduce the occurrence of micro-luminescence The etched sidewalls of the diodes produce non-radiative recombination.

Description of drawings

FIG. 1 is a flow chart of steps of an embodiment of a method for fabricating a micro-LED with reduced non-radiative recombination according to the present invention.

FIG. 2 is a schematic cross-sectional view of an embodiment of a light-emitting diode epitaxy wafer according to the present invention.

FIG. 3 is a schematic cross-sectional view of an embodiment of an etched LED epiwafer according to the present invention.

4 is a schematic cross-sectional view of an embodiment of an etched LED epiwafer provided with a passivation layer according to the present invention.

FIG. 5 is a schematic cross-sectional view of another embodiment of an etched LED epiwafer provided with a passivation layer according to the present invention.

FIG. 6 is a flow chart of steps of yet another embodiment of the method for manufacturing a micro-LED with reduced non-radiative recombination according to the present invention.

FIG. 7 is a schematic structural diagram of an embodiment of a manufacturing machine for reducing non-radiative recombination micro-LEDs according to the present invention.

Description of reference numerals: 20-LED epiwafer; 200-etched LED epiwafer; 21-substrate; 22-etched trench; 23-first-type semiconductor layer; 24-platform structure; 241 - etched sidewall; 243 - top surface; 25 - active layer; 26 - contact electrode; 27 - second type semiconductor layer; 29 - passivation layer; 411-conveying device; 42-carrying plate; 43-first atomic layer deposition chamber; 430-reaction chamber; 45-second atomic layer deposition chamber; 450-atomic layer deposition chamber.

Detailed ways

Please refer to FIG. 1 , which is a flow chart of steps of an embodiment of a method for fabricating a micro-LED with reduced non-radiative recombination of the present invention. Please refer to FIG. 2 to FIG. 5 , at least one LED epiwafer 20 is provided, wherein the LED epiwafer 20 includes a substrate 21 , a first type semiconductor layer 23 , an active layer 25 and a second type Semiconductor layer 27 . In the process of light-emitting diodes, the first-type semiconductor layer 23 , the active layer 25 and the second-type semiconductor layer 27 can be sequentially grown on the substrate 21 by metal-organic chemical vapor deposition (MOCVD), wherein the active layer 25 is located on the substrate 21 . The space between the first-type semiconductor layer 23 and the second-type semiconductor layer 27 is shown in FIG. 2 . For example, the substrate 21 is made of sapphire (Sapphire), silicon carbide (SiC), silicon (Si), gallium arsenide (GaAs), lithium metaaluminate (LiAlO2), magnesium oxide (MgO), zinc oxide (ZnO), gallium nitride (GaN), aluminum nitride (AlN), or indium nitride (InN) and other single crystal substrates, the first type semiconductor layer 23 is an N-type semiconductor, the active layer 25 is a plurality of layers of quantum wells (QuantumWell), and the second type The semiconductor layer 27 is a P-type semiconductor.

The LED epiwafer 20 is etched, and a plurality of etching trenches 22 and a plurality of mesa structures 24 are formed on a surface of the LED epiwafer 20 , wherein the etching trench 22 exposes the first-type semiconductor layer 23 and forms a The etched LED epiwafer 200 is shown in step 11 and FIG. 3 .

The platform structure 24 of the etched LED epiwafer 200 includes a plurality of etched spacers 241 , wherein the etched spacers 241 are located at the junction of the platform structure 24 and the etched trench 22 , and the platform structure 24 has on the etched sidewalls 241 . The first type semiconductor layer 23 , the active layer 25 and the second type semiconductor layer 27 are exposed. For example, the etching grooves 22 can be checkerboard-shaped grooves, and the platform structures 24 are protrusions arranged in a matrix, which can be square protrusions or circular protrusions.

During the etching process, the structure of the LED epiwafer 20 will be destroyed, and at least one dangling bond and/or at least one defect will be formed on the etched sidewall 241 of the etched LED epiwafer 200, so that Etching the spacers 241 results in non-radiative recombination.

Since the size of the micro-LED and the mesa structure 24 is very small, for example, between 10-100 um, it is similar to the size of the sidewall 241 etched on the micro-LED and the mesa structure 24 . Therefore, when the sidewall 241 is etched to generate non-radiative recombination, the luminous brightness of the micro-LEDs is bound to be greatly affected.

Therefore, the present invention performs a first atomic layer deposition on the etched LED epiwafer 200 in a first temperature range, as shown in step 13 . During the first atomic layer deposition on the etched LED epiwafer 200 , the precursor gas may react with the etched LED epiwafer 200 and repair the etched LED epiwafer 200 The floating bonds and defects of the platform structure 24 of the wafer 200 can preliminarily prevent the non-radiative recombination of the etched sidewalls 241 .

The second atomic layer deposition is performed on the etched LED epiwafer 200 after the first atomic layer deposition in the second temperature range, and the first-type semiconductor layer 23 and the active layer on the etched sidewalls 241 of the platform structure 24 are 25 and the second type semiconductor layer 27 to form a passivation layer 29, as shown in step 15 and FIG. 4 . In an embodiment of the present invention, the passivation layer 29 can completely cover the etched trench 22 , eg, cover the bottom and sides of the etched trench 22 , to prevent non-radiative recombination in the etched sidewalls 241 of the mesa structure 24 . In an embodiment of the present invention, the precursor gases used in the first atomic layer deposition and the second atomic layer deposition include organometallic compounds, organosilicon compounds, silicon chloride compounds, organoaluminum compounds, TMA, water, glycols, ozone or ethanol, and the passivation layer 29 may be aluminum oxide (Al2O3).

In the embodiment of the present invention, the first temperature interval in which the first atomic layer deposition is performed is different from the second temperature interval in which the second atomic layer deposition is performed. When the first temperature interval is smaller than the second temperature interval, the deposition time of the first atomic layer can be prolonged, and the reaction time of repairing the dangling bonds and defects of the etched spacers 241 can be increased. When the first temperature range is greater than the second temperature range, the activity of the precursor gas during the deposition of the first atomic layer can be improved, which is also beneficial to repair the dangling bonds and defects of the etching sidewall 241 . Specifically, the above steps 13 to 15 can be applied to batch atomic layer deposition (Batch ALD) or spatial atomic layer deposition (Spatial ALD). Furthermore, the time for deposition of the first atomic layer may be greater or substantially greater than the time for deposition of the second atomic layer.

The following table shows the experimental data when only the second atomic layer deposition was performed, and the first atomic layer deposition was not performed, the first temperature interval was smaller than the second temperature interval, and the first temperature interval was greater than the second temperature interval. The luminous intensity difference (%) in the table below is the intensity of the micro-LEDs formed under the above process conditions, compared with the intensity of the micro-LED epiwafer 200 formed with silicon dioxide (SiO2) of about 5000A on the surface. In addition, the following data does not immediately perform the first and/or second atomic layer deposition after the etching of the LED epiwafer 20 is completed, so the following data are not absolute.

As shown in Table 1, when the first atomic layer deposition is not performed, the brightness of the micro-LEDs cannot be effectively improved. As shown in Table 2, when the first temperature range is 200° C. and the second temperature range is 220° C., the brightness of the micro-LEDs is slightly improved. As shown in Table 3, when the first temperature range is 270° C. and the second temperature range is 220° C., the brightness of the micro-LEDs is significantly improved. As shown in Table 4, when the first temperature range is 150° C. and the second temperature range is 220° C., the brightness of the micro-LEDs is also significantly improved. It can be explained that when the first temperature range of the first atomic layer deposition is different from the second temperature range of the second atomic layer deposition, the luminous brightness of the micro-LED can be improved. Of course, the data in the above table are only experimental data of the present invention, and are not intended to limit the scope of the rights of the present invention.

In another embodiment of the present invention, the passivation layer 29 may also be provided on a top surface 243 of the mesa structure 24 by the second atomic layer deposition, wherein the passivation layer 29 not only covers the etched sidewall spacers 241 of the mesa structure 24 , but also Extends to the top surface 243 of the platform construction 24 as shown in FIG. 5 . In addition, the passivation layer 29 is disposed on the etched sidewalls 241 and the top surface 243 of the mesa structure 24 , and the passivation layer 29 can also be used as a reflective layer for reflecting the light sources generated by the micro-LEDs and the mesa structure 24 .

In practical application, the contact electrode 26 can be disposed on the platform structure 24 first, and then the passivation layer 29 can be disposed, wherein the passivation layer 29 can be in contact with the contact electrode 26, or the passivation layer 29 can be set, and then the passivation layer 29 can be placed on the platform. Contact electrodes 26 are provided on the structure 24 . After the passivation layer 29 is disposed, the etched LED epiwafer 200 can be cut along the etching trench 22 to form a plurality of micro LEDs.

In an embodiment of the present invention, contact electrodes 26, a reflective layer, a transparent current diffusion layer, etc. may be disposed on the etched LED epiwafer 200, which are common structures in the light-emitting diode technical field, and the above structures are not the present invention. The focus of the invention will not be described in detail for this reason.

Please refer to FIG. 6 , which is a flow chart of the steps of another embodiment of the method for fabricating a micro-LED with reduced non-radiative recombination according to the present invention. Please refer to FIG. 2 to FIG. 5 , first, at least one LED epiwafer 20 is provided, wherein the LED epiwafer 20 includes a substrate 21 , a first-type semiconductor layer 23 , an active layer 25 and a second type semiconductor layer 27 .

Etching the LED epi-wafer 20 to form a plurality of etching trenches 22 and a plurality of mesa structures 24 on the LED epi-wafer 20 , and forming an etched LED epi-wafer 200 , as in step 11 and shown in Figure 3. The platform structure 24 of the etched LED epiwafer 200 includes a plurality of etched sidewalls 241 , wherein the etched sidewalls 241 are located at the junction of the platform structure 24 and the etched trench 22 , and the etched sidewalls 241 have exposed first spacers. The first type semiconductor layer 23 , the active layer 25 and the second type semiconductor layer 27 . For example, the etching grooves 22 can be checkerboard-shaped grooves, and the platform structures 24 are protrusions arranged in a matrix, which can be square protrusions or circular protrusions.

The etched LED epiwafer 200 is placed in a reaction chamber, and a repair gas is delivered into the reaction chamber, as shown in step 33 . In practical applications, the repairing gas can be selected according to the materials of the first-type semiconductor layer 23 , the active layer 25 and the second-type semiconductor layer 27 , wherein the repairing gas includes oxygen, nitrogen or ozone.

An AC voltage is supplied to an AC coil adjacent to the reaction chamber, so that the repair gas in the reaction chamber becomes plasma, wherein the plasma repair gas will react with the etched LED epiwafer 200 and repair The etched LED epiwafer 200 is shown in step 35 . For example, when the first-type semiconductor layer 23 , the active layer 25 and the second-type semiconductor layer 27 are indium gallium nitride (InGaN), the repair gas can be nitrogen, and the etched sides of the mesa structure 24 are repaired by the plasmatized repair gas 241's floating keys and defects. In an embodiment of the present invention, the reaction chamber may be a general physical vapor deposition chamber or an atomic layer deposition chamber, so that the etched LED epiwafer 200 can be repaired with a plasma repairing gas.

In addition, when repairing gas and ozone, there is no need to supply AC voltage to the AC coil. As long as a certain concentration of ozone is provided in the reaction chamber, the ozone can react with the etched LED epiwafer 200 and repair the dangling bonds and defects of the etched side 241 of the platform structure 24 . Therefore, step 35 is not an essential step of the present invention, and whether to perform step 35 can be determined according to the type of repair gas. In addition, after the repairing gas is delivered to the reaction chamber, the temperature of the reaction chamber and the repairing gas can be increased.

Atomic layer deposition is performed on the repaired etched LED epiwafer 200 , and a passivation layer 29 is formed on at least one etched side 241 of the mesa structure 24 , wherein the passivation layer 29 covers the etched side of the mesa structure 24 The first type semiconductor layer 23 , the active layer 25 and the second type semiconductor layer 27 on the side 241 are shown in step 37 . In an embodiment of the present invention, the precursor gas used in atomic layer deposition includes organometallic compounds, organosilicon compounds, silicon chloride compounds, organoaluminum compounds, TMA, water, glycol, ozone or ethanol, and the passivation layer 29 may be aluminum oxide (Al2O3).

The repairing reaction and the ALD process described in the above steps 33 to 37 can be performed in the same or two different reaction chambers. One reaction chamber or the same atomic layer deposition chamber is used for repairing reaction and atomic layer deposition process. Specifically, the above steps 33 to 37 can be applied to batch atomic layer deposition (Batch ALD) or spatial atomic layer deposition (Spatial ALD). Also the time for the repair reaction can be greater or much greater than the time for atomic layer deposition.

Please refer to FIG. 7 , which is a schematic structural diagram of an embodiment of a manufacturing machine for reducing non-radiative recombination of micro-LEDs according to the present invention. Please refer to FIG. 1 , the fabrication machine 40 for micro-LEDs includes a transfer chamber 41 , at least one first atomic layer deposition chamber 43 and at least one second atomic layer deposition chamber 45 , wherein the transfer chamber 41 The first atomic layer deposition chamber 43 and the second atomic layer deposition chamber 45 are connected, and the transfer chamber 41 , the first atomic layer deposition chamber 43 and the second atomic layer deposition chamber 45 are kept at low pressure or vacuum.

In an embodiment of the present invention, the transfer chamber 41 includes at least one transfer device 411 , for example, the transfer device 411 can be a robotic arm, wherein the transfer device 411 is used to carry and transfer at least one etched LED epiwafer 200 . In practical application, a plurality of etched LED epiwafers 200 can be placed on a carrier plate 42 , and the carrier plate 42 and the etched LED epiwafers 200 are carried and conveyed by the conveying device 411 . The conveying device 411 can expand and contract relative to the first atomic layer deposition chamber 43 and the second atomic layer deposition chamber 45 , and convey the etched LED epiwafer 200 to the first atomic layer deposition chamber 43 and the second atomic layer deposition chamber 45 The atomic layer deposition chamber 45 or the etched LED epiwafer 200 is taken out from the first atomic layer deposition chamber 43 and the second atomic layer deposition chamber 45 .

The transfer device 411 first transports the etched LED epiwafer 200 into the first atomic layer deposition chamber 43 , and aligns the etched LEDs in the first atomic layer deposition chamber 43 at a first temperature range The volume epiwafer 200 is subjected to the first atomic layer deposition. During the first atomic layer deposition in the first atomic layer deposition chamber 43 , the precursor gas can be used to repair dangling bonds and defects on the etched sidewall spacers 241 of the mesa structure 24 , so as to preliminarily avoid non-radiative recombination of the etched sidewall spacers 241 .

Then, the transfer device 411 takes out the etched LED epiwafer 200 subjected to the first atomic layer deposition from the first atomic layer deposition chamber 43 and transfers it to the second atomic layer deposition chamber 45 . The second atomic layer deposition chamber 45 performs the second atomic layer deposition on the etched LED epiwafer 200 in a second temperature range, so as to deposit the second atomic layer on the etched sidewalls 241 of the etched LED epiwafer 200 A passivation layer 29 is formed, wherein the passivation layer 29 covers the first type semiconductor layer 23 , the active layer 25 and the second type semiconductor layer 27 on the etched sidewall spacers 241 of the mesa structure 24 to prevent etching on the mesa structure 24 The side walls 241 undergo non-radiative recombination.

In the embodiment of the present invention, the first temperature interval is different from the second temperature interval. When the first temperature range is smaller than the second temperature range, the time for the deposition of the first atomic layer can be prolonged, and the time for repairing the dangling bonds and defects on the etched sidewall spacers 241 can be increased. When the first temperature range is greater than the second temperature range, the activity of the precursor gas during the deposition of the first atomic layer can be increased, which is also beneficial to repair the dangling bonds and defects of the etching sidewall 241 .

In another embodiment of the present invention, the above-mentioned first atomic layer deposition chamber 43 can be a reaction chamber 430 , and the second atomic layer deposition chamber 45 can be an atomic layer deposition chamber 450 . The reaction chamber 430 and the atomic layer deposition chamber 450 are connected to the transfer chamber 41 , and the etched LED epitaxy is transferred between the reaction chamber 430 and the atomic layer deposition chamber 450 through the transfer device 411 of the transfer chamber 41 Wafer 200.

The conveying device 411 first conveys the etched LED epiwafer 200 to the reaction chamber 43 , and then conveys a repairing gas into the reaction chamber 430 . In an embodiment of the present invention, the micro-LED fabrication machine 40 may include an AC coil, wherein the AC coil is adjacent to the reaction chamber 43 and used to form a magnetic field in the reaction chamber 430, so that the reaction chamber The repair gas within body 430 becomes plasma. The plasmaized repair gas will react with the etched LED epiwafer 200 and repair the etched LED epiwafer 200 , for example, the first type semiconductor on the etched sidewall 241 of the mesa structure 24 is repaired Dangling bonds and defects of the layer 23 , the active layer 25 and the second type semiconductor layer 27 . In practical application, the repairing gas can be selected according to the materials of the first-type semiconductor layer 23 , the active layer 25 and the second-type semiconductor layer 27 , wherein the repairing gas includes oxygen, nitrogen, and ozone.

In addition, when the repair gas is ozone, there is no need to supply AC voltage to the AC coil. As long as a certain concentration of ozone is provided in the reaction chamber, the ozone can react with the etched LED epiwafer 200 .

The transfer device 411 takes out the repaired and etched LED epiwafer 200 in the reaction chamber 430 and transfers it to the atomic layer deposition chamber 450 . The atomic layer deposition chamber 450 performs an atomic layer deposition on the etched LED epiwafer 200 to form a passivation layer 29 on the etched sidewall spacers 241 of the mesa structure 24 , for example, cover the etched side with the passivation layer 29 The first type semiconductor layer 23 , the active layer 25 and the second type semiconductor layer 27 on the wall 241 prevent non-radiative recombination in the etched sidewall spacer 241 of the mesa structure 24 .

Advantages of the present invention:

It can effectively repair defects and dangling bonds on the etched sidewalls of the micro-LED and platform structures, and form a passivation layer on the micro-LEDs and platform structures to reduce the etched sidewalls of the micro-LEDs produce non-radiative recombination. .

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Modifications should be included in the scope of the patent application of the present invention.

Claims (10)

1. A method for fabricating a micro light emitting diode with reduced non-radiative recombination, comprising:

providing at least one etched LED epitaxial wafer, wherein the etched LED epitaxial wafer comprises a plurality of etched grooves and a plurality of platform structures, each platform structure comprises a first type semiconductor layer, an active layer and a second type semiconductor layer, and the active layer is positioned between the first type semiconductor layer and the second type semiconductor layer;

performing a first atomic layer deposition on the etched LED epitaxial wafer within a first temperature range; and

and performing second atomic layer deposition on the etched light-emitting diode epitaxial wafer subjected to the first atomic layer deposition in a second temperature interval, and forming a passivation layer on the first type semiconductor layer, the active layer and the second type semiconductor layer on at least one etched side wall of the platform structure, wherein the first temperature interval is different from the second temperature interval.

2. The method of claim 1 wherein the first atomic layer deposition is used to repair at least one dangling bond or at least one defect of the etched LED epitaxial wafer, and the second atomic layer deposition is used to dispose the passivation layer on a top surface of the mesa structure.

3. The method of claim 1, wherein a precursor gas used in the first atomic layer deposition and the second atomic layer deposition comprises an organometallic compound, an organosilicon compound, a silicon chloride compound, water, a glycol, ozone, or ethanol.

4. A method for fabricating a micro light emitting diode with reduced non-radiative recombination, comprising:

providing at least one etched LED epitaxial wafer, wherein the etched LED epitaxial wafer comprises a plurality of etched grooves and a plurality of platform structures, each platform structure comprises a first type semiconductor layer, an active layer and a second type semiconductor layer, and the active layer is positioned between the first type semiconductor layer and the second type semiconductor layer;

placing the etched LED epitaxial wafer into a reaction cavity, and delivering a repair gas into the reaction cavity, wherein the repair gas reacts with the etched LED epitaxial wafer; and

and performing atomic layer deposition on the etched LED epitaxial wafer, and forming a passivation layer on the first type semiconductor layer, the active layer and the second type semiconductor layer on at least one etched side wall of the platform structure.

5. The method of claim 4, wherein the atomic layer deposition is performed in the reaction chamber.

6. The method of claim 4, comprising applying an AC voltage to an AC coil adjacent to the reaction chamber to form a plasma of the repair gas in the reaction chamber, wherein the plasma of the repair gas reacts with the etched LED epitaxial wafer to repair at least one dangling bond or at least one defect of the etched LED epitaxial wafer, and the second atomic layer is deposited on a top surface of the mesa structure to form the passivation layer.

7. The method as claimed in claim 4, wherein the atomic layer deposition uses a precursor gas comprising an organometallic compound, an organosilicon compound, a silicon chloride compound, water, a glycol, ozone or ethanol.

8. The method of claim 4, wherein the repair gas is nitrogen, oxygen, or ozone.

9. A micro LED manufacturing machine for reducing non-radiative recombination, comprising:

a transmission cavity including at least one transmission device for transmitting at least one etched LED epitaxial wafer, wherein the etched LED epitaxial wafer includes a plurality of etching trenches and a plurality of mesa structures, the mesa structure includes a first type semiconductor layer, an active layer and a second type semiconductor layer, the active layer is located between the first type semiconductor layer and the second type semiconductor layer;

at least one first atomic layer deposition cavity connected to the transfer cavity, wherein the transfer device transfers the etched LED epitaxial wafer to the first atomic layer deposition cavity, and performs a first atomic layer deposition on the etched LED epitaxial wafer within a first temperature range in the first atomic layer deposition cavity; and

at least one second atomic layer deposition cavity connected with the transmission cavity, wherein the transmission device transmits the etched light emitting diode epitaxial wafer subjected to the first atomic layer deposition to the second atomic layer deposition cavity, and performs a second atomic layer deposition on the etched light emitting diode epitaxial wafer in a second temperature interval in the second atomic layer deposition cavity so as to form a passivation layer on the first type semiconductor layer, the active layer and the second type semiconductor layer on at least one etched side wall of the platform structure, wherein the first temperature interval is different from the second temperature interval.

10. A micro LED manufacturing machine for reducing non-radiative recombination, comprising:

a transfer chamber including at least one transfer device for transferring at least one etched LED epitaxial wafer, wherein the etched LED epitaxial wafer includes a plurality of etched trenches and a plurality of mesa structures, the mesa structure includes a first type semiconductor layer, an active layer and a second type semiconductor layer, the active layer is located between the first type semiconductor layer and the second type semiconductor layer;

at least one reaction cavity connected to the transmission cavity, wherein the transmission device transmits the etched LED epitaxial wafer to the reaction cavity and transmits a repairing gas into the reaction cavity, so that the repairing gas reacts with the etched LED epitaxial wafer; and

at least one atomic layer deposition cavity connected to the transfer cavity, wherein the transfer device transfers the etched light emitting diode epitaxial wafer in the reaction cavity to the atomic layer deposition cavity, and performs an atomic layer deposition on the etched light emitting diode epitaxial wafer in the atomic layer deposition cavity to form a passivation layer on the first type semiconductor layer, the active layer and the second type semiconductor layer on at least one etched sidewall of the mesa structure.

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