Invasive pneumococcal infection is the most common cause of HUS in Taiwan. Positive T-Ag activation and a direct Coombs' test are rapid predictors of SP-HUS in children with invasive pneumonia.

No abstract

This paper reports Al 0.27 Ga 0.73 N/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) with stacked Al 2 O 3 /HfO 2 gate dielectrics by using hydrogen peroxideoxidation/sputtering techniques. The Al 2 O 3 employed as a gate dielectric and surface passivation layer effectively suppresses the gate leakage current, improves RF drain current collapse and exhibits good thermal stability. Moreover, by stacking the good insulating high-k HfO 2 dielectric further suppresses the gate leakage, enhances the dielectric breakdown field and power-added efficiency, and decreases the equivalent oxide thickness. The present MOS-HEMT design has demonstrated superior improvements of 10.1% (16.4%) in the maximum drain-source current (I DS, max ), 11.4% (22.5%) in the gate voltage swing and 12.5%/14.4% (21.9%/22.3%) in the two-terminal gate-drain breakdown/turn-on voltages (BV GD /V ON ), and the present design also demonstrates the lowest gate leakage current and best thermal stability characteristics as compared to two reference MOS-HEMTs with a single Al 2 O 3 /(HfO 2 ) dielectric layer of the same physical thickness.

Novel Al 0.75 Ga 0.25 N/Al x Ga 1−x N/Al 0.75 Ga 0.25 N/AlN metal-oxide-semiconductor heterostructure field-effect transistors (MOS-HFETs) with symmetrically-graded widegap Al x Ga 1−x N channel (x = 0.75 → 0.25 → 0.75) grown on a SiC substrate are investigated. Al 2 O 3 was devised as the gate dielectric by using a non-vacuum ultrasonic spray pyrolysis deposition (USPD) technique. Device characteristics with respect to different etch depths of the source/drain recesses were studied. For a 2μm gate length (L G), the present widegap V-shape-channel MOS-HFET has shown improved maximum drain-source current density (I DS,max) of 299.3 A/mm at V DS = 20 V, I DS density at V GS = 0 V (I DSS0) of 153.9 mA/mm, on/off-current ratio (I on /I off) of 1.4 × 10 7 , extrinsic transconductance (g m,max) of 16.7 mS/mm, two-terminal off-state gate-drain breakdown voltage (BV GD) of −379 V, and three-terminal on-state drain-source breakdown voltage (BV DS) of 339 V. Besides, superior deep-UV sensing performance with high spectral responsivity (SR) of 1780 (810.2) A/W at wavelength λ = 250 (300) nm are also achieved. INDEX TERMS Al x Ga 1−x N, MOS-HFET, symmetrically-graded, widegap channel, Al 2 O 3 , non-vacuum ultrasonic spray pyrolysis deposition, spectral responsivity, deep-UV.