Increased Productivity for blue LED Production
using 5x3" wafers in Planetary Reactors®

Improved productivity was obtained using the AIX 2400G3HT production type Planetary Reactor^® in the 5x3" configuration for the growth of green and blue GaN based LEDs. The new reactor design allows an increase of wafer surface of 87% without additional costs. The optimum reactor geometry was found by extensive modeling efforts and allows maximum temperatures above 1400ºC with a temperature uniformity of less then 1ºC across the wafer surface. Group III precursor efficiency is as high as 20% and the thickness, composition and wavelength uniformity is in the range of 1% standard deviation which is a necessary prerequisite for a low cost production of blue and green light emitting diodes (LED).

Sophisticated analysis techniques such as high resolution X-rays diffraction, transmission electron microscopy and low temperature photoluminescence was used to establish the material quality which is reported as close to the best physical properties known so far. The detailed investigations were carried out within the EU funded RAINBOW research project. The consortium consisting of Thomson CSF, CRHEA, Epichem, the Universities of Aveiro, Erlangen and Surrey, and AIXTRON developed the first complete European Al-Ga-In-N material base. This culminated in the mass production technology of Ultra High Brightness Light Emitting Diodes (UHB-LED) in various colors from ultra violett to yellow, and the fabrication of blue nitride based laser diodes. That is one additional advantage of the reactor which can be used to process devices for a wide range of applications for various market segments with one multifunctional Planetary Reactor^® as an epitaxial tool. This 3" multiwafer technology was successfully transferred from the AIXTRON application laboratory to various customer sites which start production now.

This improvement in semiconductor technology based on the multiwafer 3inch Planetary Reactor^® for III-V components targets cost reduction of two important, closely related and fast growing markets. Firstly, high brightness outdoor lighting as used in large outdoor displays, traffic signals, automobile lighting, etc., and secondly the market of high density optical disk storage as used in the multimedia environment.