Proceedings Article | 20 November 2007
KEYWORDS: Light emitting diodes, Etching, Aluminium gallium indium phosphide, Photoresist materials, Semiconducting wafers, Luminous efficiency, Electrodes, Resistance, Wet etching, Plasma enhanced chemical vapor deposition
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.
