GaN-Based LEDs and Lasers on SiC

Abstract

At OSRAM Opto Semiconductors GaN based devices are grown using metalorganic vapor phase epitaxy (MOVPE) on SiC substrates. SiC as a substrate offers many advantages both from epitaxial and device processing point of view. For production on an industrial scale both a stable epitaxial process and a low cost chip technology had to be developed. By using an optimized GaInN MQW for the active region and an improved chip technology as well as package design leading to a better light extraction the LED optical output at 460 nm exceeds now 7 mW at 20 mA in a 5 mm radial lamp. By optimizing buffer growth and GaInN active region, p- and n-contacts, grinding and polishing processes as well as facet cleaving the first European GaN based violet laser diode could be realized. The device had an emission wavelength of 420 nm, a threshold current density of less than 17 kA/cm2 at 25 V and operated under pulsed current injection at room temperature.