Compared with silicon (Si), silicon carbide (SiC) is a wide-bandgap semiconductor with superior physical and chemical properties and is recognized as one of the most promising materials for applications in high-power and high-temperature semiconductor devices [1,2] and severe, hard biomaterials [1-3]. The superior material properties include high strength, high thermal conductivity, high temperature stability, high refractive index, low thermal expansion, low density, variable wide bandgap, and chemical inertness . In terms of physical properties of semiconductor electronics, crystalline SiC exhibits a larger bandgap (2.3-3.4 eV), a higher breakdown field (30 × 105 V/cm), a higher thermal conductivity (3.2-4.9 W/cm K), and a higher saturation velocity (2 × 107 cm/s) than Si . In terms of mechanical properties, SiC specifically exhibits excellent hardness and wear resistance, among others. The Knoop hardness of SiC is about 2480 kg/mm2, which is comparable to that of other hard materials such as diamond (7000 kg/mm2) and Al2O3 (2100 kg/mm2), and is much higher than that of Si (850 kg/mm2) . The wear resistance value of SiC is 9.15 comparable with that of diamond, which is 10, and Al2O3, which is 9.00 . Also, SiC has a high Young’s modulus of 700 GPa, about 3.5 times higher than that of Si . In terms of chemical properties, SiC is resistant to most acids, but can be etched by alkaline hydroxide bases at melting temperatures (>600°C). Note that SiC does not melt, but sublimes above 1800°C (Si melts at 1410°C). The SiC surface can be passivated by the formation of a thermal SiO2 layer, but the oxidation rate is very slow compared to Si . Combining its excellent mechanical properties and high temperature stability, SiC offers new possibilities for developing more challenging applications of MEMS devices than those possible with Si [1,7-9].
|Title of host publication||Nanostructured Thin Films and Coatings|
|Subtitle of host publication||Functional Properties|
|Number of pages||26|
|Publication status||Published - 2010 Jan 1|
All Science Journal Classification (ASJC) codes
- Materials Science(all)