Evaluation of threading dislocation density of strained Ge epitaxial layer by high resolution x-ray diffraction
Evaluation of threading dislocation density of strained Ge epitaxial layer by high resolution x-ray diffraction
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高分辨率X射线衍射评价应变Ge外延层的穿透位错密度
DOI：
10.1088/1674-1056/26/12/127309
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发表时间：
2017-12-01
影响因子：
1.7
通讯作者：
Zhang, He-Ming
中科院分区：
文献类型：
--
作者：
Miao, Yuan-Hao;Hu, Hui-Yong;Zhang, He-Ming
分析锗硅层中螺纹位错密度（TDD）对于激光器、发光二极管（led）、光电探测器（pd）、调制器、波导、金属氧化物半导体场效应晶体管（mosfet）以及硅基单片光子学集成的发展至关重要。采用刻蚀法和透射电镜（TEM）分析了锗外延层的TDD。然而，高分辨率x射线衍射（HR-XRD）摇摆曲线为分析锗层中的TDD提供了一种可选的方法。利用摇摆曲线测量TDD的理论模型首次应用于锌-闪锌矿半导体。本文将该方法推广到应变锗硅层的情况。测量了HR-XRD 2 θ / ω扫描，利用Ge（004）单晶摇摆曲线计算了应变Ge外延层的TDD。通过仪器的入射光束发散、晶体尺寸和晶体试样的曲率来减除半最大值时摇摆曲线的全宽度（FWHM）。计算得到样品A和B的tdd分别为1.41 x 108 cm（-2）和6.47 x 108 cm（-2）。此外，我们认为用这种方法计算的tdd就是锗外延层中的平均位错密度。
The analysis of threading dislocation density (TDD) in Ge-on-Si layer is critical for developing lasers, light emitting diodes (LEDs), photodetectors (PDs), modulators, waveguides, metal oxide semiconductor field effect transistors (MOSFETs), and also the integration of Si-based monolithic photonics. The TDD of Ge epitaxial layer is analyzed by etching or transmission electron microscope (TEM). However, high-resolution x-ray diffraction (HR-XRD) rocking curve provides an optional method to analyze the TDD in Ge layer. The theory model of TDD measurement from rocking curves was first used in zinc-blende semiconductors. In this paper, this method is extended to the case of strained Ge-on-Si layers. The HR-XRD 2 theta/omega scan is measured and Ge (004) single crystal rocking curve is utilized to calculate the TDD in strained Ge epitaxial layer. The rocking curve full width at half maximum (FWHM) broadening by incident beam divergence of the instrument, crystal size, and curvature of the crystal specimen is subtracted. The TDDs of samples A and B are calculated to be 1.41 x 108 cm(-2) and 6.47 x 108 cm(-2), respectively. In addition, we believe the TDDs calculated by this method to be the averaged dislocation density in the Ge epitaxial layer.