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

This paper presents the results of unintentionally doped4H-SiC epilayers grown on n-type Si-faced 4H-SiC substrates with 8°off-axis toward the [11overline 2 0] direction by low pressurehorizontal hot-wall chemical vapour deposition. Growth temperatureand pressure are 1580~°C and 10⁴~Pa, respectively. Good surfacemorphology of the sample is observed using atomic forcemicroscopy (AFM) and scanning electron microscopy (SEM). Fourier transforminfrared spectroscopy (FTIR) and x-ray diffraction (XRD) are used tocharacterize epitaxial layer thickness and the structural quality of thefilms respectively. The carrier concentration in the unintentional 4H-SiChomoepitaxial layer is about 6.4×10¹⁴~cm^-3 obtained byc--V measurements. Schottky barrier diodes (SBDs) are fabricated on theepitaxial wafer in order to verify the quality of the wafer and to obtaininformation about the correlation between background impurity and electricalproperties of the devices. Ni and Ti/4H-SiC Schottky barrier diodes withvery good performances were obtained and their ideality factors are 1.10 and 1.05respectively.