氮化镓基垂直结构发光二极管隧穿型电流匀化结构研究

项目名称： 氮化镓基垂直结构发光二极管隧穿型电流匀化结构研究

项目编号： No.61204052

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 信息四处

项目作者： 郭恩卿

作者单位： 中国科学院半导体研究所

项目金额： 28万元

中文摘要： 本项目采用MOCVD外延生长技术在氮化镓基LED外延结构上插入氮化镓基隧穿PN结来使LED工作时注入电流密度均匀分布。本项目研究具有一定电流密度注入下高动态电阻的氮化镓基隧穿PN结外延生长，研究隧穿结作为电流扩展层纵向支路使电流扩展层具有的电流分布特性，研究电流分布的变化与LED光效，可靠性以及使用寿命之间的关系。在大注入电流密度下，氮化镓基发光二极管的电流分布非常不均匀，限制了其光效的提高，也降低了其可靠性和使用寿命。理论计算表明如果额定电流密度注入时纵向动态电阻大并且外加偏压低的电流扩展层能较理想地实现发光二极管的电流均匀分布。而PN隧穿二极管具有接近无穷大的动态电阻,因为PN隧穿二极管在正向偏置下电压升高到一定值后电流会出现饱和。这一特性非常适合于用来加强发光二极管的电流扩展层的电流扩展能力，实现近乎理想的均匀注入电流分布。

中文关键词： 隧穿；LED；垂直结构；电流分布；动态电阻

英文摘要： In this project, PN tunneling junction, used as high dynamic resistance layer at certain current density as required to improve the curent spreading, are going to be inserted in GaN base LED epilayers during MOCVD process. We will research on the epitaxy method of GaN tunneling junction, the I-V characterastic of the current spreading layer with GaN tunneling junction inserted in it, the relationship of LED's current distribution to it's efficacy, reliability and lifetime. At large injection current density,the current distribution in GaN based LED is quite non uniform, which is not conducive to LED's efficacy and reliability. Thoery calculations indicate that large longitudinal dynamic resistance with low voltage bias and certain current density injection as required could satify the demand of LED's uniform current distribution. Fortunitely, the PN tunneling junction has infinite dyanamic resistance, because when its forward voltage increased a certain lever its current will saturate. So PN tunneling junction could be used in current spreading layer to improve it's current spreading ability, making the LED's current distribution close to ideal uniform.

英文关键词： Tunneling；LED；Vertical structure；current distribution；dynamic resistance