Sapphire-etched vertical-electrode nitride-based semiconductor light-emitting diode (SEVENS LED) fabricated by the wet etching technique

Abstract

A sapphire-etched vertical-electrode nitride-based semiconductor (SEVENS) light-emitting diode (LED) has been fabricated by a selective wet etching technique. The light output power of the SEVENS LED is substantially enhanced compared with a conventional NiAu lateral-electrode (LE) GaN-based LED formed on a sapphire substrate. The light output power of the SEVENS LED is not saturated up to as high as 300 mA junction current, being a notable improvement over that (250 mA junction current) of the LE LED. The 250 mA light output power of the SEVENS LED with an entire sapphire-removed surface is 4.3 times larger than that of the LE LED. The variations of peak wavelength and full width at half maximum are less for the SEVENS LED compared to the LE LED. This performance improvement is attributed to the transfer of the sapphire substrate to a silicon substrate and the microroughened surface self-formed by wet etching of the sapphire substrate. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)