Time filter

Source Type

Zuo C.-C.,Jiangsu University | Zuo R.,Jiangsu University | Tong Y.-Z.,Peking University | Tong Y.-Z.,Sino Nitride Semiconductor Co. | And 2 more authors.
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2016

Based on the density functional theory with CASTEP pakage of Materials Studio, the surface adsorption process of m-plane GaN grown by MOVPE was investigated. For the initial adsorption sites for GaCH3 and NH3 on m-plane GaN surface, the optimized adsorption energy, atomic distance, density of states, charge density distribution and electron population were all obtained. The calculation results show that for GaCH3 adsorption, the most stable position is optimized Ga brg2 site, where the adsorption energy is the lowest, and Ga in GaCH3 forms Ga-N and Ga-Ga covalent bonds with neighboring surface atoms, respectively. For NH3 adsorption, the most stable position is optimized N brg2 site, where the adsorption energy is the lowest, and N in NH3 forms N-Ga covalent bond with surface Ga atom. By comparing the charge density distributions and the electron populations for GaCH3 and NH3 on the optimized adsorption sites, the existance of the above covent bonds is confirmed. © 2016, Chinese Ceramic Society. All right reserved.


Sun Y.,Peking University | Yu T.,Peking University | Dai J.,Sino Nitride Semiconductor Co. | Wang N.,Sino Nitride Semiconductor Co. | And 6 more authors.
CrystEngComm | Year: 2014

Patterned sapphire substrates (PSS) are generally applied and have been proved to be effective in the increasing light extraction efficiency and crystal quality of GaN-based LEDs. The time evolution growth of GaN on triangle platform shaped PSS with an n-plane inclined surface and triangle cone shaped PSS with a part r-plane surface has been performed to research the nucleation and 3D growth mechanisms of GaN grown on the PSS. After the low temperature GaN growth process and high temperature ramping process, the small islands of GaN rotate and gather on the n-plane surface near the ridges of the triangle platform shaped PSS. Then the next 850 seconds high temperature growth process of GaN shows a 3D behavior. From the observations of SEM, it is believed that <1-100>, <11-20> and <0001> are the three preferred growth directions for GaN and the (1-10k) and (0001) planes are the two preferable planes during the GaN 3D growth. This journal is © the Partner Organisations 2014.


Patent
Sino Nitride Semiconductor Co | Date: 2015-01-21

The present application discloses a composite substrate used for GaN growth, comprising a thermally and electrically conductive layer (1) with a melting point greater than 1000C and a GaN mono-crystalline layer (2) bcated on the thermally and electrically conductive layer (1). The thermally and electrically conductive layer (1) and the GaN mono-crystalline layer (2) are bonded through a van der Waals force or a flexible medium layer (3). The composite substrate can further include a reflective layer (4) located inside, in the lower portion, or at a lower surface of the GaN mono-crystalline layer. In the disclosed composite substrate, iso-epitaxy required by GaN epitaxy is provided; crystalline quality is improved; and a vertical structure LED can be directly prepared. Further, a thin GaN mono-crystalline layer greatly reduces cost, which is advantageous in applications.


Patent
Sino Nitride Semiconductor Co | Date: 2012-05-22

The present application discloses a composite substrate used for GaN growth, comprising a thermally and electrically conductive layer (1) with a melting point greater than 1000 C. and a mono-crystalline GaN layer 2 (2) located on the thermally and electrically conductive layer (1). The thermally and electrically conductive layer (1) and the mono-crystalline GaN layer 2 (2) are bonded through a van der Waals force or a flexible medium layer (3). The composite substrate can further include a reflective layer (4) located at an inner side, a bottom part, or a bottom surface of the mono-crystalline GaN layer 2. In the disclosed composite substrate, iso-epitaxy required by GaN epitaxy is provided; crystalline quality is improved; and a vertical structure LED can be directly prepared. Further, a thin mono-crystalline GaN layer 2 greatly reduces cost, which is advantageous in applications.


Patent
Sino Nitride Semiconductor Co | Date: 2015-01-21

The present application discloses method for preparing a composite substrate for GaN growth. The method comprises: first growing a GaN mono-crystalline epitaxial layer on a sapphire substrate, then bonding the GaN epitaxial layer onto a temporary substrate with an epoxy-type instant adhesive, lifting off the sapphire substrate by laser, then bonding the GaN epitaxial layer on the temporary substrate with a thermally and electrically conductive substrate, shedding the temporary substrate, and so obtaining the composite substrate in which the GaN layer of face-up gallium polarity is bonded to the thermally and electrically conductive substrate. When the GaN layer on the sapphire substrate is directly bonded to the thermally and electrically conductive substrate and the sapphire substrate is lifted off by laser, a composite substrate in which a GaN epitaxial sheet of face-up nitrogen polarity is bonded to the thermally and electrically conductive substrate is obtained. The composite substrate prepared in the present invention not only has homo-epitaxy and improves the quality of crystals but also can be used directly for the preparation of LEDs with a vertical structure, and merely uses a thin layer of GaN mono-crystalline , greatly reducing costs and possessing advantages in applications.


A method for nondestructive laser lift-off of GaN from sapphire substrates utilizing a solid-state laser is disclosed in the present invention, wherein, a solid-state laser is used as the laser source, and a small laser-spot with a circumference of 3 to 1000 micrometers and a distance of two farthest corners or a longest diameter of no more than 400 micrometers is used for laser scanning point-by-point and line-by-line, wherein the energy in the small laser-spot is distributed such that the energy in the center of the laser-spot is the strongest and is gradually reduced toward the periphery. According to the present invention, a nondestructive laser lift-off with a small laser-spot is achieved, and a scanning mode of the laser lift-off is improved, thereby a lift-off method without the need of aiming is achieved. As a result, the laser lift-off process is simplified, and the efficiency is improved while the rejection rate is reduced, such that the obstacles of the industrialization of the laser lift-off process are removed.


Patent
Sino Nitride Semiconductor Co. | Date: 2012-07-23

The present application discloses a composite substrate with a protective layer for preventing metal from diffusing, comprising: a thermally and electrically conductive layer (2) having a melting point of greater than 1000 C., and a GaN mono-crystalline layer (1) located on the thermally and electrically conductive layer (2). At least the side wall of the composite substrate is cladded with a protective layer (3) for preventing metal from diffusing. The composite substrate not only takes account of the homoepitaxy required for GaN epitaxy and improves the quality of the crystals, but also can be used directly to prepare LEDs with vertical structures and significantly reduce costs. The disclosed composite substrate effectively avoids the pollution of experimental instruments by the diffusion and volatilization of a metal material during the growth of MOCVD at high temperature.


Patent
Sino Nitride Semiconductor Co. | Date: 2012-05-22

A method for preparing a composite substrate for GaN growth includes: growing a GaN monocrystal epitaxial layer on a sapphire substrate, bonding the GaN epitaxial layer onto a temporary substrate, lifting off the sapphire substrate, bonding the GaN epitaxial layer on the temporary substrate with a thermally and electrically conducting substrate, shedding the temporary substrate, and obtaining the composite substrate in which the GaN layer having a surface of gallium polarity is bonded to the conducting substrate. If the GaN layer on the sapphire substrate is directly bonded to the conducting substrate, after the sapphire substrate is lifted off, a composite substrate in which a GaN epitaxial layer having a surface of nitrogen polarity is bonded to the conducting substrate. The disclosed composite substrates have homoepitaxy and improved crystal quality; they can be used for forming LED and other devices at greatly reduces costs.


Patent
Sino Nitride Semiconductor Co | Date: 2015-01-14

The present application discloses a composite substrate with a protective layer for preventing metal from diffusing, comprising: a thermally and electrically conductive layer (2) having a melting point of greater than 1000C, and a GaN mono-crystalline layer (1) located on the thermally and electrically conductive layer (2). At least the side wall of the composite substrate is cladded with a protective layer (3) for preventing metal from diffusing. The composite substrate not only takes account of the iso-epitaxy required for GaN epitaxy and improves the quality of the crystals, but also can be used directly to prepare LEDs with vertical structures and significantly reduce costs, and at the same time, the composite substrate effectively avoids the problem of pollution of experimental instruments caused by the diffusion and volatilization of a metal material during the growth of MOCVD at high temperature.


Patent
Sino Nitride Semiconductor Co | Date: 2012-03-14

A solid-state laser lift-off apparatus comprises: a solid-state laser (1), a light beam shaping lens (3), motors of oscillating mirrors (5,7), oscillating mirrors (4,6), a field lens (9), a movable platform (10), an industrial control computer and control software (8). The light beam shaping lens (3) is behind the solid-state laser (1), shaping the laser beam from the solid-state laser (1) into required shape. The motors of oscillating mirrors (5,7) are in front of the field lens (9), controlling the movement of the oscillating mirrors (4,6) according to the instruction of the control software (8) to implement different light beam scanning paths. A lift-off method for applying the solid-state laser lift-off apparatus uses a small laser spot to perform scanning, and enables damage-free separation of GaN from a sapphire substrate.

Loading Sino Nitride Semiconductor CO. collaborators
Loading Sino Nitride Semiconductor CO. collaborators