The fabrication of high-brightness and high-power InGaAlP single-side red LED

Abstract

In this paper, it is reported that the design and fabrication of high-brightness and high-power InGaAlP single-side red LED with electrodes which are interdigitated with the fingers. High-brightness and high-power InGaAlP LED is a new kind of visible light LED developed in recent years, which is driven by large current capacity, high luminous efficiency and excellent heat resistance. It has been used in various fields, such as large area displays, traffic lights, brake lights and so on. As compared with the conventional double-side LED, the single-side LED is more flexible to integrate with other devices and its fabrication is simplified. The size of chip is 1mm². The fabrication of single-side LED, essentially, is the same as conventional LED, involving photolithography, PECVD SiO₂, wet etching, evaporating, lift off and rapid thermal annealing using four masks. To control the widths of mesa and N electrode precisely, the selecting etch technique has been adopted, using HCL: H₂O:H₂O₂ as the InGaAlP etching solution. I-V characteristics, light emission spectrum, luminous flux, luminous intensity and luminous efficiency of this LED have been measured. The characteristics are obtained with turn-on voltage of 1.5V and forward current of 400mA at its forward voltage of 3V. The peak wavelength is 635nm, which corresponds to red light, and the Full Width of Half Maximum is 16.4nm at injection current of 350mA. The luminous intensity is 830 mcd. The color coordinates is x=0.6943, y=0.3056 and the color index is 18.4. So we will conclude that the high-brightness and high-power InGaAlP single-side red LED will become new focus in both scientific research and industrial investment for its wide application.