Dielectric strength of thermal oxides on 6H-SiC and 4H-SiC

Abstract

This work reports on the dielectric strength of oxide layers formed by thermal oxidation of silicon carbide (SiC). SiC epilayers grown homoepitaxially on the silicon face of 6H-SiC and 4H-SiC substrates were oxidized in dry or wet ambient at 1100 °C. The dielectric strength was investigated using metal–oxide-semiconductor capacitors and was found to be tightly bound to 10 MV/cm for oxide thicknesses around 65 nm and independent of the SiC polytype and substrate doping. Considering the current-voltage characteristics in the prebreakdown region, dry oxides exhibit superior quality. Fowler–Nordheim tunneling was identified as the limiting current mechanism in the dry oxides. The corresponding barrier heights between the two SiC polytypes and thermal silicon dioxide were determined.

Effect of substrate orientation and crystal anisotropy on the thermally oxidized SiO2/SiC interface

“…4͑a͒ can be fit to a Fowler-Nordheim plot with the c-axis capacitor yielding a barrier height of 2.8 eV, consistent with previous reports. 21,22 The I-V curve for the ͑1120͒ orientation yields a lower barrier height of 2.2 eV. However, methods such as the corona charging technique 23 are needed for conclusive determination of orientation-dependent barrier heights.…”

Properties of thermally oxidized and nitrided Zr-oxynitride thin film on 4H–SiC in diluted N2O ambient

“…20. The source of negative Q eff may be ascribed to the existence of acceptor interface traps that acted as fixed charges when not located in the majority band edge [60]. In this work, the lowest Q eff of 1.2 Â 10 13 cm À2 , was obtained by film oxidized/nitrided in diluted N 2 O (10%), which was relatively small as compared to other samples with higher concentration of N 2 O.…”

Structural inhomogeneity and silicon enrichment of buried SiO2 layers formed by oxygen ion implantation in silicon

“…20 However, the carbon itself is unlikely to cause the oxide degradation: the oxides thermally grown on silicon carbide show good insulating properties despite a permanent carbon supply from the substrate. [21][22][23] Apparently then, the conducting defects in the SIMOX BOX are mainly related to the clusters of excess silicon. Indeed, etch-back experiments reveal the presence of defects protruding all the way through the BOX layer into the superficial silicon, 24 indicating a laterally inhomogeneous phase separation in the BOX.…”