Current–voltage, capacitance–voltage–temperature, and dlts studies of Ni|6H-SiC Schottky diode

In this paper, we give a systematical description of Ni|6H-SiC Schottky diode by current–voltage $I(V)$ characteristics at room temperature and capacitance–voltage $C(V)$ characteristics at various frequencies (10–800 kHz) and various temperatures (77–350 K). The $I(V)$ characteristics show a double-barrier phenomenon, which gives a low and high barrier height ($\phi_{bn}^{\operatorname{L}}$ = 0.91 eV, $\phi_{bn}^{\operatorname{H}}$ = 1.55 eV), with a difference of $\Delta\phi_{bn}$ = 0.64 eV. Also, low ideality factor $n^{\operatorname{L}}$ = 1.94 and high ideality factor $n^{\operatorname{H}}$ = 1.22 are obtained. The $C$–$V$–$T$ measurements show that the barrier height $\phi_{bn}$ decreases with decreasing of temperature and gives a temperature coefficient $\alpha$ = 1.0 $\times$ 10$^{-3}$ eV/K and $\phi_{bn}$ ($T$ = 0 K) = 1.32 eV. Deep-level transient spectroscopy (DLTS) has been used to investigate deep levels in the Ni|6H-SiC Schottky diode. The traps signatures such as activation energies $E_\alpha$ = 0.50 $\pm$ 0.07 eV, capture cross-section $\sigma$ = 1.8 $\times$ 10$^{-20}$ cm$^2$, and defect concentration $N_T$ = 6.2 $\times$ 10$^{13}$ cm$^{-3}$ were calculated from Arrhenius plots.