In this paper, a study is presented of the effect of Fe in the buffer layer on the laser lift-off (LLO) of GaN high electron mobility transistors (HEMTs). AlGaN/GaN HEMTs grown on Fe-doped and unintentionally doped buffer layers were separated from sapphire substrates using a 248 nm KrF excimer laser lift-off system. We analyzed the variations of the crystal characteristics, two-dimensional electron gas (2DEG) characteristics and the strain state of AlGaN/GaN HEMT films before and after LLO by the x-ray diffraction, Hall and Raman methods. The measurement of the distribution of elemental Fe in the GaN buffer layer was performed by secondary ion mass spectroscopy. The results show that a peak Fe concentration of 9.56 × 10 18 cm −3 appears at the interface. Moreover, the crystal quality and 2DEG characteristics of the Fe-doped GaN film obviously degenerated, with the formation of micro-cracks under the threshold laser separation energy density ( Es ). In t...

中文翻译：

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缓冲层中的Fe对AlGaN / GaN HEMT薄膜激光剥离的影响：现象和机理

本文研究了缓冲层中的Fe对GaN高电子迁移率晶体管（HEMT）的激光剥离（LLO）的影响。使用248 nm KrF准分子激光剥离系统将生长在掺Fe和无意掺杂的缓冲层上的AlGaN / GaN HEMT与蓝宝石衬底分离。我们通过X射线衍射，霍尔和拉曼方法分析了LLO前后AlGaN / GaN HEMT薄膜的晶体特性，二维电子气（2DEG）特性和应变状态的变化。GaN缓冲层中元素Fe的分布的测量通过二次离子质谱法进行。结果表明，在界面处出现峰值Fe浓度为9.56×10 18 cm -3。此外，掺杂Fe的GaN薄膜的晶体质量和2DEG特性明显退化，在阈值激光分离能密度（Es）下形成微裂纹。在...