III-NITRIDE MULTIWAFER MOCVD SYSTEMS FOR BLUE-GREEN LED MATERIAL

The worldwide demand for ultra-high-brightness blue and green LEDs has driven the development of MOCVD for Al-Ga-In-N alloy systems towards efficient multiwafer technology. This new MOCVD approach has been deve loped using a unique growth initiation cycle which provides material o f superior quality and increased lateral thickness uniformities in the 7 in x 2 in to 15 in x 2 in Planetary Reactor(R), which is to our kno wledge the largest Nitride MOCVD reactor in the field of successful pr oduction of blue LEDs. For proper growth initiation for blue-green LED material it is essential that heating from room temperature to 1000 d egrees C can be done in less than 2 min and the cool down from 1000 to 500 degrees C takes place in 3 min. The growth initiation cycle has b een demonstrated to yield device quality GaN with X-ray FWHM of 30 arc sec and excellent PL uniformity. The key to the excellent results is t he high flexibility of this unique MOCVD process which can be used bet ween 10 and 1000 mbar, a variety of total flow rates and extremely pre cise temperature control and uniformity across the entire reactor and the substrates. Using all these flexible parameters in the appropriate way allows the required growth rate to be adjusted and the necessary control on In composition in InGaN with the successful demonstration o f blue LEDs to be obtained. (C) 1997 Elsevier Science S.A.