Effects of Process Parameters on the Microstructural Characteristics of DC Magnetron Sputtered Molybdenum Films on Graph

  • PDF / 1,555,530 Bytes
  • 8 Pages / 595.276 x 790.866 pts Page_size
  • 91 Downloads / 248 Views

DOWNLOAD

REPORT


RESEARCH ARTICLE-PHYSICS

Effects of Process Parameters on the Microstructural Characteristics of DC Magnetron Sputtered Molybdenum Films on Graphite Substrate Muhammad Azhar Iqbal1 · Zuhair S. Khan1 · Nisar Ahmed1 · Asghar Ali1 Received: 4 January 2020 / Accepted: 18 August 2020 © King Fahd University of Petroleum & Minerals 2020

Abstract Graphite, due to its extreme purity and high-temperature stability, is considered as the material of choice for nuclear fusion reactors. However, it undergoes rapid oxidation and erosion at extreme environmental conditions like those experienced by the plasma-facing components (PFCs) of a fusion reactor. On the other hand, molybdenum (Mo) does offer a combination of thermal, mechanical, and chemical properties that make it an aspirant candidate for PFCs and other applications demanding substantial physical, chemical, and thermal stability as well as significant thermal conductivity. Mo films on graphite is one of the attractive options to sustain against such harsh environmental conditions. Here, in this work, we develop Mo films over graphite substrate through sputter deposition and analyze the effects of process parameters like the sputter power and the substrate temperature on the morphology and film quality. It is shown that an increase in sputter power, as well as substrate temperature, induces significant changes in the topography of the films. For low-temperature depositions, the grain morphology does not change with increasing sputter power, however, for relatively higher substrate temperatures, significant changes in morphology are observed with increasing sputter power. Similarly, dependences of crystallite size, film roughness, and electrical conductivity are discussed with changing sputter power and substrate temperature. Our results suggest that the kinetic energy of the sputtered Mo particles plays a crucial role in determining the final film quality. This study manifests that optimum sputter parameters guarantee quality Mo films over graphite substrate. Keywords DC magnetron sputtering · Mo thin films · Sputter power · Substrate temperature · Resistivity

1 Introduction International thermonuclear experimental reactor (ITER) is emerging as an auspicious energy project to mitigate the uprising energy demand in the future [1]. The cravings to add fusion reactors in the energy supply chain demands more stable and damage tolerant materials. The achievements in material research may enable plants for longer operations, which is the main stimulus behind the development of novel schemes and to test robust materials for plasma-facing components (PFCs) [2]. In the advent of fusion science and technology, graphite was considered as a suitable PFC but chemical erosion and presence of carbon impurities in core plasma put a question mark on its credibility

B 1

Zuhair S. Khan [email protected] U.S.-Pakistan Center for Advanced Studies in Energy, National University of Sciences and Technology, Islamabad 44000, Pakistan

[3]. Unarguably, graphite is an efficient heat-toler