SiC epitaxial layers grown by chemical vapour deposition and the fabrication of Schottky barrier diodes

This paper presents the results of unintentionally doped 4H-SiC epilayers grown on n-type Si-faced 4H-SiC substrates with 8° off-axis toward the [1120] direction by low pressure horizontal hot-wall chemical vapour deposition. Growth temperature and pressure are 1580 ℃ and 10^4 Pa, respectively. Good surface morphology of the sample is observed using atomic force microscopy （AFM） and scanning electron microscopy （SEM）. Fourier transform infrared spectroscopy （FTIR） and x-ray diffraction （XRD） are used to characterize epitaxial layer thickness and the structural quality of the films respectively. The carrier concentration in the unintentional 4H-SiC homoepitaxial layer is about 6.4×10^14 cm^-3 obtained by C-V measurements. Schottky barrier diodes （SBDs） are fabricated on the epitaxial wafer in order to verify the quality of the wafer and to obtain information about the correlation between background impurity and electrical properties of the devices. Ni and Ti/4H-SiC Schottky barrier diodes with very good performances were obtained and their ideality factors are 1.10 and 1.05 respectively.