Publication Date

12-2012

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Materials Science and Engineering

Department

Materials Science and Engineering

Supervisory Committee Chair

Darryl Butt, Ph.D.

Abstract

Polycrystalline 3C silicon carbide was implanted at room temperature with 400 keV cesium ions to a dose of 1016 ions·cm-2. The samples were then annealed at 600 – 1000°C for 0-48 hours in ultra-high purity argon. The implanted zone of each sample was characterized by transmission electron microscopy and secondary ion mass spectroscopy. It is shown that the implantation resulted in a 217 ± 2 nm amorphous region with microstructural damage extending to approximately 250 nm below the surface. Recrystallization of the amorphous region was observed at 725°C, although minimal densification was observed until ≥ 800°C. Densification of the annealed samples was observed through the measurement of the implantation region thickness. Through these measurements, the as-implanted sample region was estimated as being 2.6 g·cm-3.Transmission electron microscopy revealed that recrystallization generally occurred through nucleation and growth at the interface of the amorphous and polycrystalline material. The recrystallized regions consisted of large identifiable 3C-SiC grains along with fine grained material. Image analysis was used to quantify the fraction of the crystalline phase as a function of time and temperature. The rate of recrystallization was greater at higher temperatures and appeared to follow an Arrhenius dependency. Secondary ion mass spectroscopy analysis demonstrated that most of the cesium was retained within the recrystallized microstructure.

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