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 β-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 β-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 ~3×10
⁴
(±1 V), a low leakage current density of ~1 μA/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 ~5 × 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%.