Root Mean Square Function Research Articles

Mobility model extraction for surface roughness of SiGe along (110) and (100) Orientations in HKMG bulk FinFET devices

Graphical abstractDisplay Omitted The HKMG Fin MOS device is fabricated with different interface between SiGe and SiO2.The interface roughness between the SiGe and SiO2 is extracted as a function of root mean square by analysis HRTEM.The interface roughness between the SiGe and SiO2 is modeled by corrected mobility model.Mobility of SiGe along (110) limits the total effective mobility on FinFET device.The interface roughness influences the mobility of SiGe. In this work, the FinFET HKMG MOS devices are fabricated on silicon wafer with p-substrate. The interface roughness between the SiGe and SiO2 is experimentally extracted and calculated as a function of root mean square by analysis of high resolution transmission electron microscopy. The surface-roughness dependent mobility model is then incorporated into device simulation to study the mobility of SiGe along (110) and (100) orientations of the devices. We further analyze four devices with different surface roughness along (100) and (100) orientations to demonstrate the influence of surface roughness on the total effective mobility.

Hydrodynamic function of the second-generation mitroflow pericardial bioprosthesis

Background. The hydrodynamic function of the smaller size Mitroflow Synergy stented pericardial bioprostheses has been studied in an in vitro fresh tissue aortic root model and compared with previous studies of free-sewn bioprostheses. Methods. Three valves of each of the sizes 19, 21, and 23 mm were sutured into fresh tissue aortic roots and tested in a pulsatile flow simulator using two different ventricular input impedance conditions. A high-speed camera was used to study the leaflet opening and closing configurations. Mean pressure difference as a function of root mean square forward flow, effective orifice area, regurgitant volumes, and total energy loss across the valves was measured. Results. Mean pressure difference with respect to root mean square forward flow decreased as the valve size increased. Thus effective orifice area increased as the valve size increased. The open leaflet configuration images showed that all three sizes of Mitroflow valves had a large circular orifice with minimal open leaflet deformation. All valves closed competently with no visible leakage and no closed regurgitant volume. The Mitroflow valves showed better effective orifice areas compared with previously tested frame-mounted porcine bioprostheses but lower effective orifice areas compared with porcine stentless bioprostheses; however, the open leaflet bending deformation was better than for any of the previously tested bioprosthetic valves. Conclusions. The hydrodynamic function of the Mitroflow Synergy stented pericardial bioprosthesis shows potential for good in vivo hemodynamic performance. The good hemodynamic performance combined with relative ease of implantation technique makes the pericardial valve a good valve in the aortic position, particularly in older patients with small annuli.