In this work, we have explored the use of a third species during chemical vapor deposition (CVD) to direct thin-film growth to occur exclusively on one surface in the presence of another. Using a combination of density functional theory (DFT) calculations and experiments, including in situ surface analysis, we have examined the use of 4-octyne as a coadsorbate in the CVD of ZrO 2 thin films on SiO 2 and Cu surfaces. At sufficiently high partial pressures of the coadsorbate and sufficiently low substrate temperatures, we find that 4-octyne can effectively compete for adsorption sites, blocking chemisorption of the thin-film precursor, Zr[N(CH 3 C 2 H 5 )] 4 , and preventing growth on Cu, while leaving growth unimpeded on SiO 2 . The selective dielectric-on-dielectric (DoD) process developed herein is fast, totally vapor phase, and does not negatively alter the composition or morphology of the deposited thin film. We argue that this approach to area-selective deposition (ASD) should be widely applicable, provided that suitable candidates for preferential binding can be identified.

No abstract

The significant feature of coalbed in China is the low permeability. A new unsteady seepage flow model is developed for the low permeability coalbed by considering the startup pressure gradient and methane desorption effect. Since the complexity of the problem, a new method which we call it "L-FVM" is developed, based on comparing the normal numerical calculation methods and comprehension research on FVM. The results show that L-FVM has the same precission but higher calculating velocity than normal FVM. This result is very important for monitoring the area pressure drawdown in coalbed methane engineering.

No abstract