Improved Epitaxial Growth for Micro-LEDs

(Summary) A manufacturing method for improving the uniformity of micro LED epitaxial layers. This method helps to ensure a consistent thickness and wavelength of the epitaxial layer. The method involves using a patterned substrate with receiving grooves. These grooves are strategically placed to catch the excess epitaxial material as it is grown. This prevents the uneven thickness caused by centrifugal forces during rotation. The grooves are also positioned to gradually increase the density away from the center. The epitaxial layer is grown on the grooved substrate, which helps to retain the excess material in the grooves. This results in a more uniform layer thickness and wavelength. The groove pattern can be checked to verify the effectiveness of the manufacturing method.

(Summary) This patent covers a micro LED chip design that is optimized for efficient red light emission. The chip is built using a GaAs epitaxial structure, which has a tunneling junction layer sandwiched between N-type and P-type layers. This structure enhances electron-hole recombination in the light-emitting layer, resulting in efficient red light emission. The chip has electrodes on one side and features a concave platform that exposes the N-type window layer. The tunneling junction layer is also doped for optimal electron tunneling. This helps to further improve the efficiency of the chip.

(Summary) A method for manufacturing micro-LEDs that increases LED efficiency. Micro-LEDs are typically manufactured by cutting the wafer into individual chips. This process can cause bond breakage, which reduces the efficiency of the LED. This patent describes a method to avoid this problem. The method involves growing vertical epitaxial walls around each micro-LED chip before cutting the wafer. This effectively isolates the chips, preventing bond breakage. As a result, the LED efficiency is improved.

(Summary) This patent describes a micro LED device and a method for manufacturing it. The device is composed of an epitaxial layer stack with a support layer, n-type semiconductor, an active layer, and p-type semiconductor. Electrical contact is made to the n-type and p-type semiconductors through electrodes. The method for manufacturing the device involves growing the epitaxial layer stack using techniques like MOCVD. After this, the n-type and p-type electrodes are formed separately on the exposed surfaces of the semiconductors. This process ensures that the device is manufactured with the highest level of precision and accuracy.

(Summary) This patent describes a method to reduce non-radiative recombination in micro-LEDs. Non-radiative recombination occurs when electrons and holes recombine without emitting light. This reduces the efficiency of the LED. The method involves repairing defects on the sidewalls of the mesa structures and passivating them to prevent non-radiative recombination. After etching the mesas, the repair and passivation are achieved by performing two stages of atomic layer deposition (ALD) on the etched LED epitaxial wafer. The first ALD repairs any dangling bonds or defects on the sidewalls. The second ALD deposits a passivation layer on the repaired sidewalls to reduce non-radiative recombination. This helps to increase the efficiency of the LED and reduce non-radiative recombination.

(Summary) A method for manufacturing microLEDs with improved efficiency and reliability. It involves depositing a support layer, first-type semiconductor layer, active layer, and second-type semiconductor layer on a substrate. This forms the epitaxial layered structure of the LED. Then electrodes are formed on the first and second semiconductor layers. The LEDs are then separated from the substrate and packaged. The key aspect of this method is the use of a support layer beneath the first-type semiconductor layer. This layer provides mechanical stability during the separation step. This prevents damage to the LED structure and maintains performance. This layer is the key to the improved efficiency and reliability of the microLEDs produced using this method.

(Summary) A fabrication method for Micro-LEDs that reduces the Quantum-Confined Stark Effect (QCSE) and improves the quantum efficiency. QCSE is a phenomenon caused by the internal electric field in the active region of the LED. This field can cause the LED to lose its efficiency and brightness. To prevent this, the method described in this patent grows a buried p-GaN layer on a semi-polar III-nitride substrate before the active layers and n-GaN layer. This configuration opposes the strain-induced piezoelectric field with the built-in depletion field in the active region. This minimizes the internal electric field, thus reducing the QCSE and improving the quantum efficiency of the LED.

(Summary) This patent describes an LED with improved light extraction efficiency. The LED is designed with a mesa structure with a truncated top and an elongated top portion. The top portion has a reflective contact that reflects light emitted from the quantum wells back through the mesa towards the emitting surface. This improves the light extraction efficiency. The elongated top also allows the quantum wells to be positioned at the mesa focal point without limiting the epitaxial layer thickness. This helps to maximize the light extraction efficiency of the LED.

(Summary) This method improves the efficiency of light-emitting diodes (LEDs). It involves inserting a granular layer during the epitaxy process. This layer forms V-shaped pits in the superlattice layer. These pits are then filled with a multi-quantum well layer. The V-shaped pits act as channels for hole injection into the quantum wells, increasing hole utilization and LED lighting efficiency. This method can be used to create LEDs that are more efficient and brighter than traditional LEDs.