Deep level investigation by current and capacitance transient spectroscopy in 4H-SiC MESFETs on semi-insulating substrates.

In this paper we present static measurements land defects analysis performed on 4H-SiC MESFETs on semi-insulating (SI) substrates containing vanadium. I-d-V-ds-T and I-d-V-gs-T characteristics show anomalies (Threshold voltage shift, leakage current, degradation in saturation current...). Deep defects analysis performed by capacitive transient spectroscopy (C-DLTS) proves the presence of one deep defect called E1 with an activation energy 0.32eV. The studies of C-DLTS signal with pulse duration (t(p)) and polarization voltage (V-r) confirm that E1 trap is a point defect. Current transient spectroscopy (I-DLTS) performed in the same devices confirm E1 defect and shows the presence of six levels with activation energies ranging from 0.09eV to 1.01eV. The localization and the identification of these defects is presented. Finally, the correlation between the anomalies observed on output characteristics and defects is discussed.