Papers by Author: Jun Morimoto

Abstract: A 4H-SiC trench MOSFET has been developed that features trench gates with a thick oxide layer on the bottoms of the trenches. The maximum electric field strength and gate-drain charge of this device are 46% and 38%, respectively lower than that of a conventional MOSFET. The drain-source breakdown voltage is 1400V and the specific on-resistance is 4.4mΩcm2 at a gate bias of 20V and a drain voltage of 2V.

Abstract: We have detected defects micro-pipes and a cluster of impurities in semi-insulating 6H-SiC substrates using long-wavelength infrared thermal imaging camera (IR-camera) with 8 ~ 14 µm in non-destructive and non-contact. Also we have evaluated the thermal influence of defects on the entire substrates from the observation results of scanning laser microscope (SLM) and light scattering tomography (LST). Through the process, it was certificated that the defects in the substrates could be detected with relatively macroscopic scale (8  6 mm2). Moreover, through a temperature profile processing by a 0.1 K thermal resolution, we estimated thermal behavior of the defect areas in the 6H-SiC precisely. The IR-camera is considered as effective technique for evaluating the defects in the intermediate range between micro and macro scale.

Abstract: Thermal anisotropy in 4H-, and 6H-SiC bulk single crystal wafers was studied by the PPE method. The thermal diffusivities of the [1-100] and [11-20] orientations (^c-axis) samples were higher than those of the [0001] orientation (//c-axis) samples. Moreover, the thermal anisotropies of the lattice component and the carrier component were analyzed by Raman measurement.