Antiphase boundaries in β-Sic thin films
Beta-SiC thin films are currently being grown via chemical vapor deposition (CVD) at North Carolina State University for potential use as a semiconductor material. Silicon carbide is a wide bandgap semiconductor with a high, saturated electron drift velocity and, as such, is a primary candidate material for high-temperature, high-speed, and high-frequency electronic devices. The β-SiC thin films are epitaxially grown on {100} silicon substrates by CVD of silicon and carbon from vapors of SiH4 and C2H4 entrained in H2 at a growth temperature of 1633 K. Since there is a lattice mismatch of -20% and a difference in thermal expansion coefficients of ∼10% between the silicon substrate and β-SiC, the silicon surface is reacted with C2H4 at 1583 K. for 150 s to form a converted β-SiC surface layer, approximately 5 nm thick, which helps prevent the formation of cracks during the growth of the thin films. The films are grown at a rate of ∼2 μm/h and are grown as thick as 40 μm.