Precision Argon ion mill system

所要求的精密Ar离子磨机是一种优秀的样品制备系统，用于制作先进的透射电子显微镜成像和分析所需的高质量薄样品。它既可用于TEM层的FIB(聚焦离子束)后处理，也可用于增强常规制备的样品。通过使用Ar离子磨，在FIB过程中形成的非晶面层将显著减少。此外，精密的氩离子磨机是一种关键工具，特别是对于我们小组的纳米发光研究：在我们精密的STEM中进行的低温纳米阴极发光光谱(STEM-CL)是一种独特的测量技术：实现了半导体真实结构与电子和光学性质的直接关联，最终空间分辨率为1.8 nm。我们的STEM-CL系统是我们研究项目的重要组成部分。我们目前正在我们的FIB中集成一个氦温化学发光系统，用于对选定的感兴趣样品区域进行精确的靶向制备，这些样品在FIB制备后仍然发光。然而，在STEM-CL实验中，Ga离子的束流损伤和FIB过程导致的薄非晶表面层的形成对发射光子的量子效率和空间分辨率产生了负面影响。由于Ga轰击产生的近表面点缺陷导致了过剩载流子的非辐射复合，根据申请人所在课题组多年的经验，开发了一种独特的STEM-CL样品的制备技术。FIB相关的表面损伤可以通过随后使用低能Ar离子刻蚀对受损的层进行温和的研磨来减少。因此，为了在FIB处理后最终制备出光学质量最高(即最高的化学发光效率)的TEM片层，精密的Ar离子研磨是必不可少的。FIB处理后，片层的最终变薄被用来减少无定形表面层，并直接改善样品表面。聚焦的Ar光束在光点或扫描模式下精确地蚀刻出几微米的特定区域。对于直接成像，使用二次电子探测器来观察离子束的位置并直接控制刻蚀过程。因此，可以生产出厚度、形状和没有无定形表面层的透射电子显微镜样品。这样的薄片是透射电子显微镜分析的基本要求，以避免在所制备的材料中产生误解甚至人工制品。精密的氩离子磨机能够温和地最终制备最高质量的透射电子显微镜样品，因此代表着现有制备方法的必要扩展。

The requested precision Argon ion mill is an excellent specimen preparation system for creating the high-quality thin specimens needed for advanced transmission electron microscopy (TEM) imaging and analysis. It will be used for both, post-FIB (focused ion beam) processing of TEM lamella as well as the enhancement of conventionally prepared specimens. Amorphous surface layers, formed during the FIB process, will be significantly reduced by using the Ar ion mill. This leads to a substantial improvement of the image quality in analytical TEM performed in the research group of the applicant as well as a service for other research groups, institutes, faculties and collaborations.Furthermore, the precision Argon ion mill is a key tool, in particular for the nanoscale luminescence investigations of our group: Low-temperature nano-cathodoluminescence spectroscopy performed in our sophisticated STEM (STEM-CL) is a unique measurement technique: realizing a direct correlation of the semiconductor real structure and the electronic and optical properties with an ultimate spatial resolution of 1.8 nm. Our STEM-CL system is an essential part of our research projects.We are currently integrating a He-temperature CL system in our FIB for a precise targeting preparation of selected sample areas-of-interest, which are still luminescent after FIB preparation. However, the beam damage by Ga ions and formation of thin amorphous surface layers induced by the FIB process negatively affect the quantum efficiency of the emitted photons and spatial resolution in STEM-CL experiments. Near-surface point defects generated by Ga bombardment lead to nonradiative recombination of excess carriers.Based on several years of experience in the research group of the applicant, a unique preparation technique for STEM-CL specimens has been developed. The FIB-related surface damage can be reduced by subsequent gentle milling of the damaged layers using low energy Ar ion etching. For the final preparation of TEM lamella of highest optical quality (i.e. highest possible CL efficiency) after FIB processing, a precision Argon ion milling is therefore absolutely essential.The final thinning of the lamella is used to reduce amorphous surface layers and improve the sample surfaces directly after FIB processing. A focused Ar beam precisely etches a specifically selected area of few micrometer in spot or scanning mode. For direct imaging, secondary electron detectors are used to observe the position of the ion beam and directly control the etching process. Thus, TEM specimens of targeted thickness, shape and free of amorphous surface layers can be produced. Such lamellas are an elementary requirement for TEM analysis in order to avoid misinterpretations or even artifacts in the prepared material.The precision Argon ion mill enables gentle final preparation of TEM specimens of the highest quality and thus represents an essential extension of existing preparation methods.