Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts
Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts
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DOI：
10.1116/1.4939186
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
N. Hasanov;B. Zhu;V. Sharma;Shunpeng Lu;Yiping Zhang;Wei Liu;Swee Tiam Tan;X. W. Sun;H. Demir
中科院分区：
文献类型：
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作者：
N. Hasanov;B. Zhu;V. Sharma;Shunpeng Lu;Yiping Zhang;Wei Liu;Swee Tiam Tan;X. W. Sun;H. Demir
在这项工作中，作者报告了在InGaN/ gan基倒装芯片发光二极管（led）中掺入TiW合金。详细分析了钛钨合金的优点。发现具有Ni/Ag/TiW金属堆叠的InGaN/GaN多量子阱led比具有Ni/Ag金属堆叠的InGaN/GaN多量子阱led耐高温退火性能更好。该器件的电流电压特性得到了极大的改善，光输出功率得到了增强。这些变化归因于含有钛钨的器件在退火后具有更高的反射率、更光滑的表面和更好的欧姆性能。通过比较两种器件结构的电致发光光谱，证明了TiW器件具有更好的热管理能力。总的来说，这些因素导致带有TiW的器件比没有TiW的器件表现出更高的外部量子效率。对反射器金属堆的详细x射线光电子能谱分析表明，经过退火处理后，各层之间的混合很少。
In this work, the authors report the incorporation of TiW alloy in InGaN/GaN-based flip-chip light-emitting diodes (LEDs). The advantages provided by the use of TiW are analyzed in detail. InGaN/GaN multiple quantum well LEDs with a Ni/Ag/TiW metal stack are found to tolerate high-temperature annealing better than those with a Ni/Ag metal stack. Highly improved current–voltage characteristics and enhanced optical output power are achieved for the devices with a TiW thin layer. These changes are ascribed to the higher reflectivity, smoother surface, and better ohmic properties of the device containing TiW after annealing. Better heat management of the device with TiW is demonstrated by comparing electroluminescence spectra of the two device structures. Overall, these factors resulted in devices with TiW exhibiting a higher external quantum efficiency than devices without TiW. Detailed x-ray photoelectron spectroscopy analyses of the reflector metal stacks reveal little intermixing of the layers after annea...