Publication details
Study of surface quality and subsurface damage of germanium optics produced by single point diamond nanomachining
| Authors | |
|---|---|
| Year of publication | 2019 |
| Type | Article in Proceedings |
| Conference | Proceedings Volume 11032, EUV and X-ray Optics: Synergy between Laboratory and Space VI |
| Citation | |
| Web | https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11032/2520970/Study-of-surface-quality-and-subsurface-damage-of-germanium-optics/10.1117/12.2520970.short?SSO=1 |
| Doi | http://dx.doi.org/10.1117/12.2520970 |
| Keywords | Nanomachining; Single point diamond technology; X-ray crystal optics; Germanium; Atomic force microscopy; Micro Raman spectroscopy; Rocking curve imaging |
| Description | Single point diamond nanomachining allows to finish surfaces of some hard-to-machine brittle materials as for example germanium with high shape accuracy, low surface roughness and low subsurface damage. Quality of these surfaces is sufficient when infrared or visible light wavelengths are used. However, using hard X-ray wavelengths, additional polishing of the nanomachined surface is necessary. We are developing polishing methods of germanium surfaces produced by nanomachining, while optimizing nanomachining conditions such as the cutting speed, cutting depth or tool geometry in the nanomachining centre. Micro Raman spectroscopy and atomic force microscopy (AFM) were used to study the effect of the cutting speed on the mode of the single point diamond machining (flycutting) of Ge(110) surface. Selected samples were also studied by the rocking curve imaging (RCI) at BM05 beam-line (ESRF), which serves as a test and development station for X-ray optical elements. The surface studies indicate that the amorphous layer generated by nanomachining of Ge (110) surface can be delaminated together with all structural imperfections within the chip under appropriate cutting conditions. Results of the study also show a dislocation-free single crystal lattice beneath the Ge (110) nanomachined surface, which demonstrates the potential of the applied method for the preparation of high quality surfaces for hard X-ray crystal optics. |