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/cm 2 at 25 V and operated under pulsed current injection at room temperature.

Influence of the misorientation of 6H–SiC substrate on the quality of GaN epilayer grown by MOVPE

“…Due to the lack of affordable large area GaN substrates, sapphire (Al 2 O 3 ) [8,9], silicon carbide (SiC) [10,11] and other foreign substrates [12][13][14] are widely used for nitrides epitaxy growth. Between those substrates, SiC has been widely used because it has very high thermal conductivity and relatively small lattice mismatch with GaN [15].…”

Influence of the growth temperature of AlN buffer on the quality and stress of GaN films grown on 6H–SiC substrate by MOVPE

“…Nitrides have been recognized as the most promising materials for laser diodes (LDs), light emitting diodes (LEDs) and high electron mobility transistors (HEMTs) applications [5][6][7]. Due to the lack of affordable large area GaN substrates, sapphire (Al 2 O 3 ) [8,9], silicon carbide (SiC) [10,11] and other foreign substrates [12][13][14] are widely used for nitrides epitaxy growth. 6H-SiC is considered as a better substrate than other substrates for its smaller lattice mismatch with GaN, and its higher thermal conductivity [10,11,15].…”

“…Due to the lack of affordable large area GaN substrates, sapphire (Al 2 O 3 ) [8,9], silicon carbide (SiC) [10,11] and other foreign substrates [12][13][14] are widely used for nitrides epitaxy growth. 6H-SiC is considered as a better substrate than other substrates for its smaller lattice mismatch with GaN, and its higher thermal conductivity [10,11,15]. The coefficients of thermal expansion, lattice constants, and thermal conductivity for GaN, AlN, 6H-SiC and sapphire are listed in Table 1 [15,16].…”

Aluminum monolayers on Si (111) for MBE-growth of GaN

“…GaN-based light emitting diodes (LED), laser diodes, and UV detectors have been realized on sapphire and silicon carbide (SiC) substrates [1,2]. Silicon is also interesting as substrate for GaN due to the favorable physical properties, high quality, very low cost and mature development for processing and large-scale production.…”