Selective Fabrication of SiC/Si Diodes by Excimer Laser Under Ambient Conditions

This letter presents SiC/Si diodes fabricated by the selective growth of SiC on Si substrate under ambient (atmospheric) conditions. The selective growth of beta-SiC was obtained by irradiating a high-power KrF excimer laser beam on a polymethyl methacrylate (PMMA)-coated Si wafer. The laser decomposed carbon atoms from the PMMA, which dissolve into molten Si to form SiC. The Raman spectrum of the grown samples shows a dominant band in the range of 930-990 cm(-1), i.e., the spectral region characteristic for beta-SiC. The quality of SiC can be optimized by changing the induced power. The best performing SiC/Si diode shows a good rectification ratio of similar to 3x10(4) (+/- 1 V), a low leakage current density of similar to 1 mu A/cm(2) (-1 V), and high breakdown (>200 V), which confirms the high quality of the SiC/Si interface. The doping of SiC was calculated from 1/C-2 versus V plot and found to be similar to 5 x 10(15) cm(-3). In addition, the measured photoelectric response shows a short circuit current density of 17 mA/cm(2), an open circuit voltage of 0.33 V, and a fill factor of 62%.