| AVS 65th International Symposium & Exhibition | |
| Thin Films Division | Thursday Sessions |
| Session TF+PS-ThM |
| Session: | Deposition Processes for 3D and Extreme Geometries |
| Presenter: | Maximilian Gebhard, Argonne National Laboratory |
| Authors: | M. Gebhard, Argonne National Laboratory A.U. Mane, Argonne National Laboratory D. Choudhury, Argonne National Laboratory S. Letourneau, Argonne National Laboratory D.J. Mandia, Argonne National Laboratory Y. Zhang, Argonne National Laboratory J.W. Elam, Argonne National Laboratory |
| Correspondent: | Click to Email |
An important building block for detector devices are amplifiers, such as microchannel plates (MCPs). Due to the geometry of several periodically arranged microchannels, incident electrons or irradiation can be amplified by several orders of magnitude, making MCPs highly efficient in several applications such as neutron detectors and night-goggles. The efficiency of state-of-the-art MCPs is strongly related to functional coatings, acting as resistive coating and secondary electron emission (SEE) layer. While the SEE material (e.g. Al2O3 or MgO) should exhibit a high SEE coefficient, the resistive coating must facilitate a uniform and stable electrostatic field along the pores and during operation. It was shown previously that atomic layer deposition (ALD) is capable to produce highly efficient SEE coatings (MgO) as well as a fine-tuned resistive coating directly on the MCP substrate, thereby improving the overall performance of the detector devices.[1,2] By producing highly conformal thin films over large areas and on large aspect ratios, ALD is the method of choice to produce functionalized MCPs.
One challenge in manufacturing reliable MCPs for advanced applications are external conditions like ambient temperature. With temperature gradients of 100 K or higher, the thermal coefficient of resistance (TCR) of the resistive coating plays a major role with respect to electrical transport phenomena. Positive TCRs can cause increased resistance at elevated temperatures and in due turn a collapse of the MCP’s performance. Similar determining factors are on hand for strongly decreased temperatures. A second challenge is the fluorine-based chemistry, which is currently often employed to produce ALD-functionalized MCP coatings.
We present here the development of ALD-fabricated materials, being free of fluorine chemistry and exhibiting tailored electric resistance over a broad temperature range as well as promising performance as resistive coating in MCPs. Apart from thorough process development, those transition metal-based materials were analyzed regarding their composition, structure and electrical behavior employing XPS, SEM, XRD and extended IV-measurements. Furthermore, the coatings were applied to MCPs, which were tested for their performance.
[1] A. U. Mane and J. W. Elam, Chem. Vap. Deposition, 2013 (19), 186-193
[2] M. J. Minot, B. W. Adams, M. Aviles, J. L. Bond, C. A. Craven, T. Cremer, M. R. Foley, A. Lyashenko, M. A. Popecki, M. E. Stochaj, W. A. Worstell, A. U. Mane, J. W. Elam, O. H. W. Siegmund, C. Ertley, H. Frisch and A. Elagin, Proceedings Volume 9968, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XVIII, 2016, DOI: 10.1117/12.2237331