The influence of Fe in the buffer layer on the laser liftoff (LLO) of GaN high electron mobility transistors is presented herein. LLO is performed on Fe-doped GaN films using a KrF excimer LLO system. The morphology, crystal characteristics, and 2D electron gas (2DEG) characteristics of the GaN films after LLO are characterized using a 3D optical microscope, X-ray diffraction, and Hall methods. The present work is different from previous methods because of the large-area buckling instead of cracks on the Fe-doped GaN films. The results show that the crystal quality and 2DEG characteristics of the buckled parts are significantly affected. Furthermore, a modified simulation model of the temperature and thermal-induced stress fields in the films is used to explain the buckling of the films, whose results are consistent with the characterization results. The additional absorption centers induced by the Fe impurity energy levels increase the gradient of temperature field, thereby increasing the compressive stresses in the films at the edges of the laser spots. Moreover, a higher temperature is observed at the interface between the film and the bonding glue, which results in the debonding. Therefore, Fe-doped GaN films are more prone to buckling than unintentionally doped GaN films.

中文翻译：

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激光剥离工艺后掺杂铁的 AlGaN/GaN 高电子迁移率晶体管薄膜的屈曲：现象和机制

本文介绍了缓冲层中的 Fe 对 GaN 高电子迁移率晶体管的激光剥离 (LLO) 的影响。使用 KrF 准分子 LLO 系统在 Fe 掺杂的 GaN 薄膜上执行 LLO。使用 3D 光学显微镜、X 射线衍射和霍尔方法表征 LLO 后 GaN 薄膜的形貌、晶体特性和 2D 电子气 (2DEG) 特性。目前的工作与以前的方法不同，因为 Fe 掺杂的 GaN 薄膜上的大面积屈曲而不是裂纹。结果表明，扣件的晶体质量和2DEG特性受到显着影响。此外，薄膜中温度和热致应力场的修正模拟模型用于解释薄膜的屈曲，其结果与表征结果一致。Fe杂质能级引起的额外吸收中心增加了温度场的梯度，从而增加了激光光斑边缘薄膜中的压应力。此外，在薄膜和粘合胶之间的界面处观察到更高的温度，这导致脱粘。因此，Fe 掺杂的 GaN 膜比非故意掺杂的 GaN 膜更容易发生屈曲。