The gas phase dynamics of an inverted, stagnation point flow CVD reactor were studied by both experiment and modeling. The axial centerline temperature profile in the reactor was measured by analysis of the rotational Raman spectra from the carrier gas (N or H ) as a function of the inlet flow velocity and the reactor aspect ratio. It was found that a larger temperature gradient 2 2 normal to t...

Steady and transient mass transport phenomena within an inverted, stagnation-flow, cold-wall CVD reactor were investigated by observing the concentration of a tracer species (CH4) with in situ Raman spectroscopy. The transient studies revealed that the use of matched reactor inlet velocities is crucial to minimize recirculating flow patterns and that the magnitude of the gas velocity is also im...

LPCVD is a process used in the manufacturing of the deposition of thin films on semiconductors usually ranging from a few nanometers to many micrometers. LPCVD is used to deposit a wide range of possible film compositions with good conformal step coverage. These films include a variety of materials including polysilicon for gate contacts, thick oxides used for isolation, doped oxides for global...

background: although physical activity (pa) has long been associated with cardiovascular disease (cvd), assessment of pa status has never been used as a part of cvd risk prediction tools. the aim of the present work was to examine whether the inclusion of pa status in a cvd risk model improves its predictive accuracy. methods: data from the 10‑year follow‑up (2002–2012) of the n = 2020 particip...

A novel composite membrane consisting of vertically aligned carbon nanotubes (CNTs) and parylene was successfully fabricated. Seamless filling of the spaces in CNT forests with parylene was achieved by a low-pressure chemical vapor deposition (CVD) technique and followed with the Ar/O2 plasma etching to expose CNT tips. Transport properties of various gases through the CNT/parylene membranes we...

The Silicon on Dust Substrate (SDS) is a gas-to-wafer process that produces multicrystalline silicon ribbons directly from gaseous feedstock (silane), avoiding the standard industry steps of polysilicon deposition, crystal growth, and wafering. SDS technique consists three main steps: (i) micrometric-sized powder production by grinding chunks; (ii) chemical vapor deposition (CVD) over this subs...

Abstract The growth rate of diamond by chemical vapor deposition (CVD) from microwave (MW) plasma activated CH 4 /H 2 gas mixtures can be significantly enhanced adding trace quantities N to the process mixture. Reasons for this increase remain unclear. present article reports new, self-consistent two-dimensional modeling MW and /CH plasmas operating at pressures powers relevant contemporary CVD...