SiC CVD Growth

The most common technique used to grow epitaxial SiC is CVD. The standard gas chemistry used is hydrogen-propane-silane, or TG-CsHs-SiEG, respectively. In this chemistry, C3H8 is the carbon growth precursor while SiTC is the silicon precursor. 

The cubic polytype of SiC, namely 3C-SiC, is the only form that can be grown hetero-epitaxially on Si substrates. However, there exists a 20 % lattice mismatch between these two crystal systems and the hope was that growth on a porous buffer layer might provide a means to reduce the defect density. This section presents preliminary research performed with this goal in mind. 

The first 3C-SiC deposition experiments were performed using the LPCVD cold-wall reaction system introduced in Section 3.2. The porous Si samples (10-15 % porosity) were processed at the University of Pittsburgh from n-type Si (100). The samples were then cleaned using the standard RCA cleaning method [15] before the epitaxial deposition took place. 

Two types of cold-wall experiments were performed the first on as-received porous Si and the second on oxidized porous Si in an attempt to limit the modification of the porous network during growth. 

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