Simulation and Design of Contact Geometry for Large-Area High-Power GaN-Based Light Emitting Diodes

• Main Authors: Shi-Yang Chang, 張世揚
• Other Authors: Shui-Jinn Wang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/03642006052804681493

碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 94 === 　　Recently, there are increasing interests in promoting the optoelectronic optical-electrical performance and light output power of GaN-based light emitting diodes (LEDs). Though vertical-structured GaN-based LEDs, which have been shown having a much better performance as compared to conventional lateral-structured LEDs, have been successfully developed employing laser liff-off (LLO) technology to remove the insulating sapphire substrate, insufficient doping concentration in p-GaN usually results in a poor current spreading and nonuniform light emission. Under the circumstances, the deposition of a Transparent Conducting Layer (TCL) and a contact electrode with a well-designed geometry are very necessary, especially for large-area and high power LEDs. 　　In this thesis, attempts were made for the geometry design of large area high power GaN-LEDs. ISE-TCAD was used for the theoretical calculations of optoelectronic performances of devices with various contact geometry and TCL design. Based on the simulation results, several contact geometrical designs in conjunction with a suitable TCL favored for uniform distributions of current and light emission were proposed. To further improve the uniformity of light emission, a novel method using an anisotropic etching to the top n-GaN layer of the GaN-LED was also proposed. Simulation results with an emphasis on etching depth and contour as well as related discussions were made.