On the suitability of 3C- Silicon Carbide as an alternative to 4H- Silicon Carbide for power diodes

Major recent developments in growth expertise related to the cubic polytype of Silicon Carbide, the 3C-SiC, coupled with its remarkable physical properties and the low fabrication cost, suggest that within the next years, 3C-SiC devices can become a commercial reality. Inevitably, a comparison to the most well developed polytype of SiC, the 4H-SiC, should exist. It is therefore important to develop Finite Element Method (FEM) techniques and models for accurate device design, analysis and comparison. It is also needed to perform an exhaustive investigation with scope to identify which family of devices, which voltage class and for which applications this polytype is best suited. In this work, we validate the recently developed Technology Computer Aided Design (TCAD) material models for 3C-SiC and those of 4H-SiC with measurements on power diodes. An excellent agreement between measurements and TCAD simulations was obtained. Thereafter, based on this validation, 3C- and 4H-SiC vertical power diodes are assessed, to create trade-off maps. Depending on the operation requirements imposed by the application, the developed trade-off maps set the boundary of the realm for those two polytypes and allows to predict which applications would benefit once electrically graded 3C-SiC becomes available

Diseño de estructura de materiales dieléctricos de crestas en V, transición de estructura periódica a aperiódica

[ES] Simulaciones numéricas en estructuras retroreflectivas de materiales dieléctricos, con el objetivo the definir vértices de cubos caracterizando una función retroreflectiva. Utilizando simulaciones de diferencias finitas en dominio temporal trabajando en la extensión de resultados de artículos recientes hacia una estructura aperiódica buscando un diseño con menores oscilaciones en el espectro de óptica de ondas.[EN] Numerical simulations on dielectric retroreflective structures, with the goal of defining thin arrays of corner cubes that feature robust retroreflective performance. Using finite-difference time-domain simulations working to extend calculations from a recent paper to designs with less periodicity seeking a less oscillating design in the wave-optics spectrum.Belanche Guadas, M. (2019). Diseño de estructura de materiales dieléctricos de crestas en V, transición de estructura periódica a aperiódica. http://hdl.handle.net/10251/143598TFG

Investigation of Electrically Active Defects in SiC Power Diodes Caused by Heavy Ion Irradiation

Deep-level transient spectroscopy (DLTS) and minority carrier transient spectroscopy (MCTS) are used to investigate electrically active defects in commercial silicon carbide (SiC) Schottky power diodes after heavy-ion microbeam irradiation at different voltages. The DLTS and MCTS spectra of pristine samples are analyzed and compared to devices showing or not signatures of single event leakage current (SELC) degradation. An additional peak labeled 'C' with an activation energy of 0.17 eV below the conduction band edge is observed in the DLTS spectra of a sample degraded with SELC.ISSN:0018-9499ISSN:1558-157

Dual configuration of shallow acceptor levels in 4H-SiC

Acceptor dopants in 4H-SiC exhibit energy levels that are located deeper in the band gap than the thermal energy at room temperature (RT), resulting in incomplete ionization at RT. Therefore, a comprehensive understanding of the defect energetics and how the impurities are introduced into the material is imperative. Herein, we study impurity related defect levels in 4H-SiC epitaxial layers (epi-layers) grown by chemical vapor deposition (CVD) under various conditions using minority carrier transient spectroscopy (MCTS). We find two trap levels assigned to boron impurities, B and D, which are introduced to varying degrees depending on the growth conditions. A second acceptor level that was labeled X in the literature and attributed to impurity related defects is also observed. Importantly, both the B and X levels exhibit fine structure revealed by MCTS measurements. We attribute the fine structure to acceptor impurities at hexagonal and pseudo-cubic lattice sites in 4H-SiC, and tentatively assign the X peak to Al based on experimental findings and density functional theory calculations.ISSN:1369-800