Silicon Epitaxial Reactor for Minimal Fab

Cost-effective and mass production of size-controlled wafers becomes one of the future trends for electronic devices. Herein, we design a Minimal Fab system for the growth of half-inch-diameter silicon wafer devices. Different from the conventional chemical vapour deposition (CVD) systems, a new-type of CVD reactor was designed and developed for the Minimal Fab. The minimal CVD reactor has a small reaction chamber for rapid growth processes. It employed (i) a vertical gas flow, (ii) heating modules using concentrated infrared light, (iii) chlorine trifluoride gas for quick reactor cleaning and (iv) optimized epitaxial growth conditions so that the reactor cleaning is not necessary. Reducing the total gas flow rate is an effective way to increase the wafer temperature. The heating process was further assisted by the absorption of infrared light by the precursor trichlorosilane. The slimly designed reflector could help in improving the heating speed

Magnetic-Field-Independent Ultrasonic Dispersions in the Magnetically Robust Heavy Fermion System SmOs4Sb12

Elastic properties of the filled skutterudite compound SmOs$_4$Sb$_{12}$ have been investigated by ultrasonic measurements. The elastic constant $C_{11}(\omega)$ shows two ultrasonic dispersions at $\sim$15 K and $\sim$53 K for frequencies $\omega$ between 33 and 316 MHz, which follow a Debye-type formula with Arrhenius-type temperature-dependent relaxation times, and remain unchanged even with applied magnetic fields up to 10 T. The corresponding activation energies were estimated to be $E_2$ = 105 K and $E_1$ = 409 K, respectively. The latter, $E_1$, is the highest value reported so far in the Sb-based filled skutterudites. The presence of magnetically robust ultrasonic dispersions in SmOs$_4$Sb$_{12}$ implies a possibility that an emergence of a magnetically insensitive heavy fermion state in this system is associated with a novel local charge degree of freedom which causes the ultrasonic dispersion.Comment: 5 pages, 4 figure

Potential role of group X secretory phospholipase A2 in cyclooxygenase-2-dependent PGE2 formation during colon tumorigenesis

AbstractAlthough the cyclooxygenase-2 (COX-2) pathway of the arachidonic acid cascade has been suggested to play an important role in colon carcinogenesis, there is little information concerning the identity of phospholipase A2 (PLA2) involved in the arachidonic acid release in colon tumors. Here, we compared the potencies of three types of secretory PLA2s (group IB, IIA and X sPLA2s) for the arachidonic acid release from cultured human colon adenocarcinoma cells, and found that group X sPLA2 has the most powerful potency in the release of arachidonic acid leading to COX-2-dependent prostaglandin E2 (PGE2) formation. Furthermore, immunohistological analysis revealed the elevated expression of group X sPLA2 in human colon adenocarcinoma neoplastic cells in concert with augmented expression of COX-2. These findings suggest a critical role of group X sPLA2 in the PGE2 biosynthesis during colon tumorigenesis