Molecular dynamics simulations of the growth of poly(chloro-para-xylylene) films

Parylene C, poly(chloro-para-xylylene) is the most widely used member of the parylene family due to its excellent chemical and physical properties. In this work we analyzed the formation of the parylene C film using molecular mechanics and molecular dynamics methods. A five unit chain is necessary to create a stable hydrophobic cluster and to adhere to a covered surface. Two scenarios were deemed to take place. The obtained results are consistent with a polymer film scaling growth mechanism and contribute to the description of the dynamic growth of the parylene C polymer

Temperature dependence of the growth front roughening of oligomer films

Growth front roughening characteristics of vacuum deposited pentamer 2,5-di-n-octyloxy-1,4-bis[4-(styryl)styryl]-benzene oligomer thin films, onto silicon substrates, strongly depend on the substrate temperature in the range ~20 °C–100 °C. The measured roughness exponents H increase from H≈0.4 at low substrate temperatures where growth is dominated by vacancy formation, to H≈0.7–0.8 at elevated temperatures where diffusive growth takes place. Moreover, the root-mean-square roughness amplitude and the correlation length evolve with temperature closely as an Arrhenius process with activation barrier comparable to molecule transnational and rotational barriers on oligomer surfaces.

Growth front roughening of room-temperature deposited oligomer films

Growth front scaling aspects are investigated by atomic force microscopy for oligomer 2,5-di-n-octyloxy-1,4-bis(4'-(styryl)styryl)-benzene thin films vapor deposited onto silicon substrates at room temperature. Analyses of the height–height correlation function for film thickness that are commonly used in optoelectronic devices, i.e., ranging between 15 and 300 nm, yield roughness Hurst exponents around H=0.45±0.04. Further, the root-mean-square roughness amplitude σ evolves with film thickness as a power law σ∝d^β, with β=0.28±0.05. The nonGaussian height distribution and the measured scaling exponents (H and β) suggest a roughening mechanism close to that described by the Kardar–Parisi–Zhang scenario indicating nonlinear film growth.

Roughening aspects of room temperature vapor deposited oligomer thin films onto Si substrates

Growth front scaling aspects are investigated for poly-(p-phenylene–vinylene)-type oligomer thin films vapor-deposited onto silicon substrates at room temperature. For a film thickness d in the range from 15 to 300 nm, commonly used in optoelectronic devices, measurements of the correlation function by atomic force microscopy yields roughness exponents in the range H = 0.45 ± 0.04, and an rms roughness amplitude which evolves with film thickness as a power law σ ∝ d^β with β = 0.28 ± 0.05. The non-Gaussian height distribution and the measured scaling exponents (H and β) suggest a roughening mechanism close to that described by the Kardar–Parisi–Zhang scenario which is characteristic of non-surface diffussive growth processes.

Growth front roughening of room temperature deposited oligomer thin films

AbstractGrowth front scaling aspects are investigated for PPV-type oligomer thin films vapor- deposited onto silicon substrates at room temperature. For film thickness d~15-300 nm, commonly used in optoelectronic devices, correlation function measurement by atomic force microscopy yields roughness exponents in the range H=0.45±0.04, and an rms roughness amplitude which evolves with film thickness as a power law σ∝ dβ with β=0.28±0.05. The non-Gaussian height distribution and the measured scaling exponents (H and β) suggest a roughening mechanism close to that described by the Kardar-Parisi-Zhang scenario.</jats:p