Xinyuanji realizes high-yield, efficient pure red light quantum dot MiniLED chip

Based on traditional color conversion LED devices, the color gamut is limited to about 90% NTSC, and it is difficult to achieve further breakthroughs in display effects. LED devices made of new luminescent materials such as quantum dots can achieve narrow emission half-wave widths (<20 nm) in the red, blue and green bands through the color conversion process, and the color gamut can exceed 120% NTSC. They are regarded as one of the most promising display technologies in the next generation.

However, current quantum dot LED devices still lack effective packaging design, and traditional packaging structures are still commonly used in terms of color conversion structure and chip integration. Therefore, the improvement of the luminous efficiency and stability of the device is limited.

On July 5, 2023, Shanghai Xinyuanji Semiconductor used chemical exfoliation GaN technology, and through a specially designed optical reflective layer and quantum dot color conversion technology, it realized high-yield, efficient pure red light flip-chip structure and formal structure quantum dot MiniLED chips. This major technological breakthrough will effectively reduce the cost of red light chips, improve the cost performance of products, and may accelerate the commercialization process of quantum dot display technology.

In terms of flip-chip structure quantum dot chip technology, Xinyuanji uses quantum dot glue to attach the light-emitting surface of the stripped GaN chip to the processed special optical reflective layer substrate. This optical reflective layer has specific effects on the wavelength of the excitation light source. It has high reflectivity and very high light transmittance for the wavelength band where quantum dots emit light, so as to achieve better excitation of red light quantum dots. When the thickness of red light quantum dots is less than 1 micron, after the quantum dots are fully excited, the red light chip will not leak blue light.

During the processing of quantum dot chips, Xinyuanji uses standard semiconductor processes, combined with mask alignment methods, to create a high-density dielectric layer on the side walls of the pixels to achieve complete sealing of quantum dots and resolve concerns about the reliability of quantum dots.

The characteristic curve of the product is as follows: (Chip size: 2*4mil/50*100um)

Characteristic curve:

The luminescence condition and yield rate of the product are as follows:

Table 1: Luminescence test conditions and yield rate:

In the future, based on this technology, Xinyuanji Semiconductor will further develop display device technology related to the quantum dot color conversion layer to meet the actual needs of future high-resolution display systems. Based on this quantum dot technology solution, Xinyuanji Semiconductor is developing quantum dot MIP devices with a size of less than 0.2mm*0.2mm for internationally renowned institutions.

Xiyuanji's quantum dot MIP technology has a metal electrode structure on the side wall of each sub-pixel of the GaN wafer. In addition to being conducive to the common cathode design of the pixel, this structure can also better solve the problem of optical crosstalk between independent sub-pixels. On the RGB quantum dot template (QDCC), an optical mirror with a specific structure design is used to achieve efficient excitation of red and green light. All processes use standard wafer processing technology, which does not require a large-volume transfer process. The wafer chip is directly bonded to the QDCC template, which can more easily reduce the industrial cost of MIP and achieve high-reliability pixel units. (Source: Xinyuanji)