ABSTRACTWe report the fabrication and the characterization of Metal Oxide Semiconductor (MOS) structure fabricated on thermally oxidized 3C-SiC grown by reactive magnetron sputtering. The structure and the composition of the SiO2 layer was studied by cross-sectional transmission electron microscopy (XTEM) Auger electron spectroscopy (AES). Homogeneous stoichiometric SiO2 layers formed with a well-defined interface to the faceted SiC(lll) top surface. Electrical properties of the MOS capacitor have been analyzed by employing the capacitance and conductance techniques. C-V curves shows the accumulation, depletion and deep depletion phases. The capacitance in the inversion regime is not saturated, as usually observed for wide-bandgap materials. The unintentional doping concentration determined from the 1/C2 curve was found to be as low as 2.8 × 1015 cm-3. The density of positive charges in the grown oxide and the interface states have been extracted by using high-frequency C-V and conductance techniques. The interface state density has been found to be in the order of 1011cm2-eV-1.
In this article, an influence of nitrogen implantation dosage on SiC MOS structure is analyzed using wide range of nitrogen implantation dose (between ~1013 – 1016). Authors analyzed electrical and material properties of investigated samples using C-V, I-V measurements, Raman spectroscopy, and XPS profiling. It has been shown that surface state trap density is directly connected to implantation damage and thus implantation conditions. Using research results a trap origin at given energy can be concluded.
The effect of electron irradiation with energy of 2.5 keV on the MOS structure Al/SiO2/Si capacitance-voltage (C-V) characteristics have been studied. At chosen beam energy the electron penetration depth is lower than the dielectric thickness that allows to reveal the contribution of excess carrier transport to the trap formation on the SiO2/Si interface. It was established that the electron beam irradiation leads to a significant change in the C-V characteristics slope, i.e. to to the trap formation at the interface. A study of effect of bias applied to the investigated structure before and during the electron beam irradiation was carried out. It was established that while the bias applied before irradiation practically did not affect the C-V characteristics of the investigated MOS structure, the positive voltage applied to metallization during irradiation produced a pronounced effect on the C-V curve changes. At the same time the C-V characteristics after irradiation with zero and negative voltage were very similar. The investigation of stability of changes produced by the electron beam irradiation showed that the C-V curves are slowly restored even at room temperature. An applied negative bias was found to slow down the charge relaxation process.
The Effect of Phosphorus Incorporation into SiO_2/4H-SiC (0001) Interface on Electrophysical Properties of MOS Structure