Lifetime Tests and Junction-Temperature Measurement of InGaN Light-Emitting Diodes Using Patterned Sapphire Substrates

• Published in: Journal of lightwave technology Vol. 25; no. 2; pp. 591 - 596
• Main Authors: Tsai, P.C., Chuang, R.W., Su, Y.K.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Cascading style sheets; Chemical vapor deposition; Dislocation density; Electronics; Electrons; Exact sciences and technology; Gallium nitride; Gallium nitrides; GaN; Indium gallium nitrides; junction temperature; Lifetime estimation; Light emitting diodes; light-emitting diode (LED); Microelectronic fabrication (materials and surfaces technology); Micrographs; Optoelectronic devices; patterned sapphire substrate; Photomicrographs; Power generation; Quantum well devices; Quantum wells; Sapphire; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Thermal resistance; X-ray diffraction; High resolution; Output power; Multiple quantum well; Durability; light-emitting diode (LED); patterned sapphire substrate; X ray diffraction; MOCVD; Thermal stability; Light emitting diode; Dislocation density; Temperature measurement; Microelectronic fabrication; Transmission electron microscopy; Thermal resistance; GaN; Power losses; Optoelectronic device; Power device; junction temperature; Blue light; Reliability
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2006.888234

The authors demonstrate nitride-based blue light-emitting diodes with an InGaN/GaN (460 nm) multiple quantum-well structure on the patterned sapphire substrates (PSSs) compared with conventional sapphire substrates (CSSs) using metal-organic chemical vapor deposition. According to full-width at half-maximum of high-resolution X-ray diffraction and transmission electron microscopy micrographs, the dislocation density of GaN epilayers grown on the PSS was lower than those of the CSS. It was found that the output power of devices on PSS was 26% larger than that of CSS. The lifetime defined by 50% loss in output power was 590 and 305 h at 85 degC for the PSS and CSS, respectively. It was also found that the junction temperature and thermal resistance were smaller for the PSS. These improvements are attributed to the reduction in dislocation density using PSS structure