Temperature-Dependent Electrical Characteristics of Au/Si₃N₄/4H n-SiC MIS Diode

Abstract

Electrical characteristics of the Au/Si₃N₄/4H n-SiC metal–insulator-semiconductor (MIS) diode were investigated under the temperature, $T$, interval of 160–400 K using current–voltage (I–V), capacitance–voltage ($C {-} V$) and conductance–voltage ($G/\omega {-} V$) measurements. Firstly, the Schottky diode parameters as zero-bias barrier height ($\Phi_{{\rm B}0}$) and ideality factor ($n$) were calculated according to the thermionic emission (TE) from forward bias I–V analysis in the whole working $T$. Experimental results showed that the values of $\Phi_{{\rm B}0}$ were in increasing behavior with increasing $T$ while $n$ values decreased with inverse proportionality in $n$ versus $\Phi_{{{\rm{B}}0}}$ plot. Therefore, the non-ideal I–V behavior with inhomogeneous barrier height (BH) formation has been discussed under the assumption of Gaussian distribution (GD). From the GD of BHs, the mean BH was found to be about 1.40 eV with 0.1697 standard deviation and the modified Richardson constant $A^{*}$ of this diode was obtained as 141.65 A/cm² K² in good agreement with the literature (the theoretical value of $A^{*}$ is 137.21 A/cm² K²). The relationship between $\Phi_{{\rm B}0}$ and $n$ showed an abnormal I–V behavior depending on $T$, and it was modeled by TE theory with GD of BH due to the effect in inhomogeneous BH at the interface. Secondly, according to Cheung’s model, series resistance, $R_{\rm{S}}$ values were calculated in the $T$ range of 160–400 K and these values were found to decrease with increasing $T$. Finally, the density of interface states, $D_{\rm{it}}$ was calculated and the $T$ dependence of energy distribution of $D_{\rm{it}}$ profiles determined the forward $I {-} V$ measurements by taking into account the bias dependence of the effective BH, $\Phi_{\rm{e}}$ and $n$. $D_{\rm{it}}$ were also calculated according to the Hill–Coleman method from $C {-} V$ and $G/\omega {-} V$ analysis. Furthermore, the variation of $D_{\rm{it}}$ as a function of frequency, $f$ and $T$ were determined.