We have applied and obtained numerous patents based on UV LED structures, production methods and know-how of increasing the efficiency, and related to MOCVD equipments, and applications utilized UV LEDs.
One of such our inventions what we have accomplish is that the high-temperature SiN intermediate layer, low-temperature GaNP buffer layer and low-temperature SiN buffer layer are help to reduce the crystalline dislocation.
Picture a: The cross-section of GaN layer grown over high-temperature SiN intermediate layer and its TEM image. The two TEM images are observed from two different directions of electron beams. It shows that the dislocation density in the high-temperature SiN intermediate layer is reduced by 30-50%.
Picture b: The cross-section of undoped-GaN layer used low-temperature GaNP buffer layer and its TEM image.
Employing low-temperature buffer layer, the dislocation density is reduced by less than 1-5x109cm-2 to 5x108cm-2.
These methods of reducing the dislocation density enable bring much higher productivity without any complicated process.
In order to increase the non-uniformity of composition in the light-emitting layer, inserting nanosized region of Ga droplets and SiN discrete layer for varying the diffusion length of the composition help the fluctuation of band gaps and double the light-emitting efficiency of AlInGaN.