Composites of silicon carbide (SiC) and silicon (Si) are fabricated by the reactive infiltration of molten Si into preforms of SiC particles and carbon. This product is often referred to as reaction bonded silicon carbide (RBSC). SiC materials are used in many applications due to their favorable properties including high hardness, high thermal conductivity, low thermal expansion and high stiffness. RBSC has the ability to closely match the coefficient of thermal expansion (CTE) of many low CTE components, such as Si-based semiconductor devices and optical devices. This study shows that by incorporating aluminum (Al) and/or titanium (Ti) into the composite, the thermal expansion becomes tailorable, allowing CTE match with Al_2O_3 and AlN based components. Moreover, these alloy additions provide increased thermal conductivity. Additions of Ti and/or Al to these composites can raise the thermal conductivity more than 10 %, while keeping most of the favorable properties of standard RBSC. Herein, the properties of Si:SiC, Al-Si:SiC and Ti-Si/SiC composites are compared, and possible thermal management applications are explored. Properties evaluated include density, Young's modulus, specific heat, thermal diffusivity, thermal conductivity, and thermal expansion. (Si, SiC, RBSC, Thermal Conductivity, Thermal Expansion, Composite).
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