Rodrigo Palmieri

Improvement of SiO2/4H-SiC interface properties by oxidation using hydrogen peroxide

The effect of using H2O2 in the thermal growth process of dielectric films on n-type 4H-SiC substrates has been investigated. In comparison to conventional oxide growth using H2O, we found that the interface trap density is reduced close to the conduction band edge of 4H-SiC. This electrical improvement is correlated with the decrease in SiCxOy compounds at the SiO2/4H-SiC interface region as confirmed by two independent methods. These results point to the use of H2O2 as an alternative passivating agent of SiO2/4H-SiC interface electrically active defects.

Trapping of majority carriers in SiO2/4H-SiC structures

We compared SiO2/SiC interface characteristics for three different oxidation processes (dry-oxygen, water-containing oxygen and water-containing nitrogen atmospheres). Metal-oxide-semiconductor (MOS) structures were fabricated on 8 ◦ off-axis 4H-SiC(0001) n- and p-type epitaxial wafers. Electrical characteristics were obtained by I –V measurements, high-frequency capacitance–voltage (C–V ) and ac conductance (G–V and G–ω) methods. The samples were also characterized by x-ray photoelectron spectroscopy. Results evidence a remarkable difference between n- and p-type doped samples. The p-type samples showed effective oxide charge density up to three orders of magnitude higher than n-type. This fact was explained by the capturing of majority carriers in near interface oxide traps.

SiO2/SiC Interfacial Region: Presence of Silicon Oxycarbides and Effects of Hydrogen Peroxide and Water Vapor Thermal Treatments

This work provides data corroborating the presence of silicon oxycarbides (SiOxCy) in the SiO2/SiC interface region. Besides, it presents results on the efficiency of hydrogen peroxide annealings for reducing the SiO2/SiC interfacial region thickness. Finally, influences of water vapor thermal treatments on dielectric films thermally grown are presented. In most of the samples, isotopes rare in nature (18O and 2H) were used in thermal treatments associated with ion beam analyses.

Improvement in the SiO2/4H-SiC Interfacial Region by Thermal Treatments with Hydrogen Peroxide

The effect of sequential thermal treatments with growth/removal steps of SiO2 films intercalated with hydrogen peroxide treatments on the SiO2/4H-SiC interfacial region thickness were investigated on both Si and C faces. In the Si face case, samples that were submitted to more H2O2 treatments presented thinner interfacial region thicknesses. In the C face case, on the other hand, no significant alteration in this region was observed.