The SEMI standard thickness, CMOS fab-friendly and large diameter QST® (QROMIS Substrate Technology) substrates enable manufacturing of commercial high-performance GaN power devices with breakdown voltages ranging from 100V to 2000V and beyond. This is achieved by utilizing a polycrystalline ceramic substrate core with the coefficient of thermal expansion (CTE) matched to GaN over a wide temperature range. In this work, the status of 200mm and 300mm commercial QST® substrates and GaN-on-QST® epi-wafers will be discussed. The production status of 650V GaN-on-QST® E-mode HEMT devices on a commercial, high volume 200mm CMOS foundry manufacturing platform is presented. Also, the results of the development work in 200mm CMOS fabs on high-quality 1,200V E-mode HEMTs are included.
We investigated the relationship between the concentration of nanosized fibers and the rheological and the rheo-optic behaviors of CNF suspensions containing unfibrillated fibers prepared by a wet refinement system (Water Jet System). The CNF suspensions behaved as a gel in which entropic elasticity was dominant, and the entanglement among fibers would be enhanced with the nanosized fiber volume fraction. The aggregates of the nanosized fibers elongated in the flow direction and deformed into elliptical shape with the applied shearing. However, the effect of these shape changes of the aggregates was barely observed on the viscosity curve. We speculate that this is due to Newtonian flow of the unfibrillated fibers (> 25% by volume) playing a significant role in the overall flow behavior of the CNF suspensions. In conclusion, for the CNF suspensions containing poorly nanosized fibers, we speculated that the nanosized and unfibrillated fibers were largely responsible for the linear response under micro-deformation and the nonlinear response such as under shear flow, respectively.
This paper reports the generation of an extra phase and the accompanying temporal effects in an asymmetric optically compensated in-pane-switching (IPS) liquid crystal (LC) system and a fringe-field-switching (FFS) liquid crystal display (LCD) exhibiting a twofold faster response speed in the switching-off process compared with that in single and symmetric IPS-LCDs and FFS LCDs for the first time. To explain the experimental results, we derived an approximate analytical formula for the optical output intensity that includes an extra phase advancement and conducted simulations to achieve normally black operation using a dynamic optical retarder.
