Papers by Author: Jean Louis Leclercq

Abstract: Silicon carbide devices limitations often originate from the quality of the substrate material. Therefore it is interesting to investigate devices fabricated on alternative source materials. Currently, CREE is the world market leader of SiC wafers. Nowadays, some new companies begin to propose alternative material. The European manufacturer SiCrystal furnishes now some epiwafers for the fabrication of 1,2kV devices. In this paper we present 4H-SiC 1.2 kV pin diodes with a JTE termination realized on a SiCrystal epiwafer. The devices exhibit a blocking voltage of 1.2 kV, a current density of 420 A.cm-2 and a specific differential series resistance of 4.4 m-⋅cm2. The yield of fabricated diodes with a breakdown voltage greater 600 V is superior to 75%.

Abstract: 6H and 4H–SiC epilayers were Al-implanted at room temperature with multiple energies (ranging from 25 to 300 keV) in order to form p-type layers with an Al plateau concentration of 4.5×1019 cm-3 and 9×1019 cm-3. Post-implantation annealing were performed at 1700 or 1800 °C up to 30 min in Ar ambient. During this process, some samples were encapsulated with a graphite (C) cap obtained by thermal conversion of a spin-coated AZ5214E photoresist. From Atomic Force Microscope measurements, the roughness is found to increase drastically with annealing temperature for unprotected samples while the C capped samples show a preservation of their surface states even for the highest annealing temperature. After 1800°C/30 min annealing, the RMS roughness is 0.46 nm for the lower fluence implanted samples, slightly higher than for unimplanted samples (0.31 nm). Secondary Ion Mass Spectroscopy measurements confirm that the C cap was totally removed from the SiC surface. The total Al-implanted fluence is preserved during postimplantation annealing. A redistribution of the Al dopants is observed at the surface which might be attributed to Si vacancy-enhanced diffusion. An accumulation peak is also observed after annealing at 0.29 9m, depth corresponding to the amorphous/crystalline interface that was determined on the as-implanted samples by Rutherford Backscattering Spectroscopy in channeling mode. The redistribution of the dopants has an impact on their electrical activation. A lower sheet resistance (Rsh= 8 k
) is obtained for samples annealed without capping than for samples annealed with C capping (Rsh= 15 k
).