Fabrication Of High Power GaN-based LED Chip

Light emitting diode(LED) is becoming a new generation of light source fortraditional light industrial upgrade by virtue of its high efficiency and lowconsumption, green and non-polluting, short response time and so on. Theimprovement of light extraction efficiency of LED chip is an important issue to besolved in LED lighting universal application. This paper begins with how to improvethe light extraction efficiency of the chip, combined with existing preparationtechnology, and high-performance and high-power GaN-based LED chip is prepared.Based on the problems of non-uniform current spreading and instableoptoelectronic properties of the high-power LED chips, the size of45mil*45milhigh-performance GaN-based LED chip is prepared. The results show that the opticalpower of the chip reaches374.35mw under a drive current of350mA. The voltageand the optical power gradually increase with the increase of the drive current and theoptical power does not decline within the scope of the changing current. It shows thatthe45mil*45mil chip prepared has stable optical and electrical properties. The surfaceof the chip emits uniformly under a current of20mA, which indicates that the currentspreads evenly. Based on the influence of the side GaN in the cutting process o f thelaser energy, a flattening edge structure of the GaN-based LED chip is prepared bythermal acid process and the result shows that the light output power improves by8.65mw.Based on the DBR structure of the conventional high-power chip manufacturingprocess having a high reflectance only in the case of small angle or vertical incident,an omni-directional metal reflector is designed and the light output power of this kindof chip improves by19.2mw compared with conventional DBR structure.For the problem of high light extraction efficiency, the output efficiency oftraditional horizontal GaN-based45mil*45mil chip simulated when the Mesa sidewallof the chip is trapezoidal and inverted trapezoidal structure. The results show that theoutput efficiency reaches31.433%when the Mesa sidewall of the chip is trapezoidal structure and the slanted angle is the critical angle of the GaN and the air interface.And the output efficiency improves by25.5%compared to the vertical-shapedstructure chip of the lateral structure. And also the trapezoidal Mesa sidewall of thechip is obtained by ICP etching.