Preparation and Characterization of Pure SiC Ceramics by HTPVT Induced by Seeding with SiC Nanoarrays.

Yu-Chen Deng,Qiang Zhi,Nan-Long Zhang,Jian-Feng Yang,Bo Wang

doi:10.3390/ma14216317

Abstract

Dense SiC ceramics were fabricated by high-temperature physical vapor transport (HTPVT) growth process using SiC nanoarrays as the crystal seeds, which was obtained by vacuum heat treatment of amorphous SiC films prepared by plasma-enhanced chemical vapor deposition (PECVD) with a porous anodic aluminum oxide (AAO) template. In the HTPVT process, two-step holding was adopted, and the temperature at the first step was controlled at 2100 and 2150 °C to avoid SiC nanoarrays evaporation, and the grain size of SiC crystal increased with the increase in temperature and decrease in the pressure of Ar. The temperature of the second step was 2300 °C, and rapid SiC grain growth and gradual densification were achieved. The prepared SiC ceramics exhibited a relative density of more than 99%, an average grain size of about 100 μm, a preferred orientation along the (0 0 0 6) plane, a Vickers hardness of about 29 GPa, a flexural strength of about 360 MPa, and thermal conductivity at room temperature of more than 200 W·m−1·K−1.

Highlights

Based on the previous research [25,26], in order to control the nucleation and optimize the microstructure of silicon carbide (SiC) ceramics more efficiently, we propose a new idea for preparing high-purity SiC ceramics by seeding with SiC nanoarrays
With the decrease in the average grain size, the flexural strength of SiC ceramics increases to 362 ± 35 MPa, and the Vickers hardness increases to 29.5 ± 0.4 GPa; these results indicate that the mechanical properties of SiC ceramics prepared via high-temperature physical vapor transport (HTPVT) can be improved significantly by the seeding with SiC nanoarrays
Dense SiC ceramics are fabricated by the HTPVT method using SiC nanoarrays as the crystal seeds, which is obtained by vacuum heat treatment of amorphous SiC films prepared by the plasma-enhanced chemical vapor deposition (PECVD) with porous anodic aluminum oxide (AAO) template

Summary

Introduction

With the development of the semiconductor industry, ultra-pure substrate materials are required to apply at high temperature and processed with corrosive compounds. Highpurity silicon carbide (SiC) materials, as a new generation of semiconductor material that can replace high-purity quartz and silicon, have become more and more important in advanced industries. SiC materials are candidates for possible application as structural and functional materials; the main role is intended for the blanket modules. Because most SiC products are high value-added and have a broad market prospect, the research on high purity SiC materials is a focus at present [1,2,3,4]

Methods

Results

Conclusion