Design and Characterization Issues in GaN-based Light Emitting Diodes
The improvements in efficiency and reliability are essential to realize high performance light emitting diodes (LEDs). Uniform current spreading is very important to enhance both efficiency and reliability simultaneously. 3-dimensional circuit modeling and analysis method was developed in order to figure out influences of current crowding on performances. The method was applied to the top-surface emitting-type LEDs of 320 × 320 μm2 size. It was found that the current crowding was closely related to the improvements in series resistance, saturation of light output power, leakage current with operational time, and endurance of electrostatic discharge (ESD). Defects due to high ESD stress were observed at current crowding area. In order to suppress the peak electric field and enhance the ESD voltage, the floating metal was inserted near the n-electrode. About 4 times larger ESD voltages were experimentally measured at LEDs with floating metal structure compared to without one. A LED with the lozenge shape is fabricated to enhance light extraction efficiency over conventional design, i.e., rectangular parallel piped chip. A lozenge shaped LED has an additional advantage of easy chip making since it has natural crystallographic cleavage planes. About 11％ larger light extraction efficiency was experimentally obtained in the lozenge shaped LEDs than conventional rectangular chips.
efficiency reliability current spreading electrostatic discharge floating metal lozenge shape
Jong-In Shim
Department of Electrical and Computer Engineering,Hanyang University,1271 Sa-dong,Ansan,Kyunggi-do 425-791,Korea
国际会议
2008亚太光通信会议(Asia-Pacific Optical Communications 2008)
杭州
英文
2008-10-26（万方平台首次上网日期，不代表论文的发表时间）