In the present work we investigate the forward current–voltage (I–V ) characteristics, over a wide temperature range 298–498 K, of Mo/4H–SiC Schottky diode for which aluminum ion implantation was used to create the high resistivity layer forming the guard ring. The (I–V ) analysis based on Thermionic Emission (TE) theory shows a decrease of the barrier height ϕ B and an increase of the ideality factor n when the temperature decreases. These anomalies are mainly due to the barrier height inhomogeneities at the metal/semiconductor interface as we get a Gaussian distribution of the barrier heights when we plot the apparent barrier height ϕ ap versus q /2kT . The mean barrier height and the standard deviation obtained values are 
B0=1.160 eV and σ0=88.049 mV, respectively.
B0=1.160 eV and σ0=88.049 mV, respectively.
However, by means of the modified Richardson plot 
versus q /kT , the mean barrier height and the Richardson constant values obtained are 
B0=1.139 eV and A *=129.425 A/cm2 K2, respectively. The latter value of 
B0 matches very well with the mean barrier height obtained from the plot ofϕap versus q/2kT. The Richardson constant is much closer to the theoretical value of 146 A/cm2 K2.
versus q /kT , the mean barrier height and the Richardson constant values obtained are B0=1.139 eV and A *=129.425 A/cm2 K2, respectively. The latter value of B0 matches very well with the mean barrier height obtained from the plot ofϕap versus q/2kT. The Richardson constant is much closer to the theoretical value of 146 A/cm2 K2.
The series resistance Rs is also estimated from the forward current–voltage characteristics of Mo/4H–SiC Schottky contact. This parameter shows strong temperature dependence. The T0 effect is validated for the 298–498 K temperature range for the used Schottky diode and provides a clear evidence for the barrier inhomogeneity at the Mo/4H–SiC interface. Finally, we note the impact of the implantation process as well as the choice of the used ion on the characterized parameters of the Schottky contact.
Keywords
- Mo/4H–SiC Schottky diodes;
- Metal/semiconductor interface;
- Barrier height inhomogeniety;
- T0 effect;
- Aluminum ion implantation
- SOURCE:SCIENCEDIRECT
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