Effect of Different Deposition Pressure on Diamond Films Deposited by Hot Filament Chemical Vapor Deposition

A hot filament chemical vapor deposition (HFCVD) method was adopted to deposit diamond films at deposition pressures ranging from 2–6 kPa. The effects of deposition pressure on the deposition rate, phase structure, and microstructure of diamond films were investigated. The surface morphology, grain size, micro-structure, and growth rate of the diamond films were analyzed using scanning electron microscopy, X-ray diffraction (XRD), and Raman spectrometry. The experimental results showed that granules on the surface exhibited increasingly compact structure with increasing deposition pressure. The diamond films deposited at various pressures have good compactness, and the particles on the film surfaces are arranged in an ordered manner. All films exhibited orientation along the (111) plane, which was the significant characteristic XRD peak of each diamond film. The (111) peak intensity was the strongest for the film prepared at 2 kPa deposition pressure. Overall, the deposition rate and grain size decreased with increasing deposition pressure, provided other deposition conditions remained unchanged. However, the densification of the microstructure and the nucleation density increased with increasing deposition pressure. Secondary nucleation became more pronounced as deposition pressure increased, and grain size decreased as nucleation density increased.

Microstructure and Ablation Behavior of Very Low-Pressure Plasma Sprayed ZrB2-Based Coatings

The effect of deposition pressure on the microstructure and ablation behavior of ZrB2 coatings deposited by very low pressure plasma spraying is investigated. The results show that under a chamber pressure less than 50 kPa, as the spray chamber pressure decreases, the porosity of the coating deposited at the same distance decreases, and the coating prepared under 100 Pa presents the lowest porosity of 1.79 %. Furthermore, among the ZrB2 coatings deposited at 100 Pa, 5 kPa, 10 kPa and 50 kPa, the dense coating deposited at 100 Pa showed the lowest ablation rate of 0.33 μm/s, 0.75±0.08 mg/s.

Deposition pressure-induced microstructure control and plasmonic property tuning in hybrid ZnO-AgxAu1-x thin films

Self-assembled oxide-metallic alloyed nanopillars as hybrid plasmonic metamaterials (e.g., ZnO-AgxAu1-x) in a thin film form are grown using a pulsed laser deposition method. The hybrid films were demonstrated to be...

Effects of Radio-Frequency Power and Deposition Pressure on Structures and Properties of Silicon-Rich Silicon Nitride Thin Films

Silicon-rich silicon nitride thin films have been grown by plasma enhanced chemical vapor deposition (PECVD) at 13.56MHZ on glass and N-type monocrystalline silicon substrate using high purity NH3,N2 and SiH4 as reactant gas sources by changing of radio-frequency (RF) power and deposition pressure. The samples were characterized by the ultraviolet-visible (UV-UIS) light transmittance spectra, Fourier transform infrared absorption spectroscopy (FTIR) and an X-ray (XRD) diffraction, respectively. The results showed that both the RF power and deposition pressure increase promote the deposition rates. However, the increase of rf power leads to the decrease of optical band gap, the increase of refractive index, and the increase of deposition pressure leads to the widening of optical band gap. The increase of rf power leads to the increase of the silicon atoms in the thin films and the transition of the films to the silicon-rich state. As the deposition pressure increase, the probability of N atoms entering the films increase and the thin films change to a nitrogen-rich state. At a certain pressure, when the rf power is changed, the average grain size in the films decrease by XRD analysis. Based on the above analysis, both the deposition pressure and rf power have an important effect on the microstructure, and optical properties of the thin films. By properly adjusting these two parameters, the silicon-rich silicon nitride films with good density can be obtained.