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

Abstract

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 $\sim 3 \times 10^{4}$ (±1 V), a low leakage current density of $\sim 1~\mu \text{A}$ /cm2 (−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 $\sim 5 \times 10^{15}$ cm $^{-3}$ . In addition, the measured photoelectric response shows a short circuit current density of 17 mA/cm2, an open circuit voltage of 0.33 V, and a fill factor of 62%.