Formation process of high reflective Ni∕Ag∕Au Ohmic contact for GaN flip-chip light-emitting diodes
Formation process of high reflective Ni∕Ag∕Au Ohmic contact for GaN flip-chip light-emitting diodes
复制标题
DOI：
10.1063/1.2730734
复制
发表时间：
2007-04
影响因子：
4
通讯作者：
Liann-Be Chang;C. Shiue;M. Jeng
中科院分区：
文献类型：
--
作者：
Liann-Be Chang;C. Shiue;M. Jeng
研究了用于倒装芯片发光二极管应用的形成欧姆接触和反射多层接触的镍、银和金的组合。研究发现，退火过程中欧姆金属和 GaN 的强烈相互扩散会导致反射率较差（465nm 波长处为 63%）。作者提出了一种两步金属化方法，首先沉积/退火Ni/Ag双层，然后沉积Au，以提高相应的反射率（高达92%）。该方法不同于传统的一步法Ni∕Ag∕Au形成方法，其中这三种金属一起沉积然后退火。二次离子质谱深度剖面表明，仅在传统的一步形成样品中存在较宽的相互扩散区域；因此，Ni∕Ag∕Au退火接触的低反射率可归因于欧姆金属向GaN的强烈相互扩散。他们提出的两步金属化方法避免了强烈的相互扩散，并且...
The combinations of Ni, Ag, and Au which form both Ohmic and reflective multilayer contacts for flip-chip light-emitting diode applications are examined. A strong interdiffusion of Ohmic metals and GaN during the annealing process is found to result in poor reflectance (63% at the wavelength of 465nm). The authors propose a two step metallization method, the Ni∕Ag double layer is first deposited/annealed followed by the deposition of Au, to improve the correspondent reflectivity (as high as 92%). This method is different from the conventional one step Ni∕Ag∕Au formation method in which these three metals are deposited together and then annealed. The secondary ion mass spectrometry depth profiles indicate that a wide interdiffusion region existed only in the conventional one step formation samples; thus the low reflectivity of Ni∕Ag∕Au-annealed contacts can be attributed to the strong interdiffusion of Ohmic metal into GaN. Their proposed two step metallization method avoids the strong interdiffusion and i...