Papers by Author: R.R Ciechonski

Abstract: The electrical properties of Al2O3 as a gate dielectric in MOS structures based on n- and p-type 4H-SiC grown by sublimation method have been investigated and compared to the properties of similar structures utilizing SiO2. The electrically active defects in the structures are studied by CV method. The results show that the type as well as spatial and energy distribution of defects in Al2O3/SiC and SiO2/SiC samples are different. The structures with Al2O3 on p-type 4H-SiC demonstrate much better C-V characteristics than the p-type 4H-SiC/SiO2 structures.

Abstract: Specific on-resistance Ron estimated from current density-voltage characteristics of Schottky diodes on thick layers exhibits variations from tens of mW.cm2 to tens of W.cm2 for different doping levels. In order to understand the occurrence of high on-state resistance, Schottky barrier heights were first estimated for both forward and reverse bias with the application of thermionic emission theory and were in agreement with a literature reported values. Decrease in mobility with the temperature was observed and its dependencies of T–1.3 and T–2.0 for moderately doped and low doped samples respectively were estimated. From deep level measurements by Minority Carrier Transient Spectroscopy, an influence of shallow boron related levels and D-center on dependence of on-state resistance was observed, being more pronounced in low doped samples. Similar tendency was observed in depth profiling of Ron. This suggests a major role of boron in a compensation mechanism thus resulting in high Ron.