Effects of discharge voltage on the characteristics of a-C:H films prepared by H-assisted Plasma CVD method

Abstract

Hydrogen bonding configurations and hydrogen content of a-C:H films deposited by H-assisted plasma CVD were investigated by Fourier transform infrared spectroscopy. Plasma parameters related to deposition rate were derived using optical emission spectroscopy. The a-C:H films contain a large number of sp 3 configurations (93%) and a few sp 2 configurations (7%). Most of the hydrogen is bonded in methyl groups which shows the structure of deposited a-C:H films is polymer-like carbon. The mass density has nearly linear decreases with increasing the hydrogen atom density, indicating that control of hydrogen content is crucial to obtain a-C:H films of high mass density. A slight increase in radical generation rate and significant increases in etching rate by hydrogen atoms lead to decrease the deposition rate when the discharge voltage increases from 170 V to 180 V.

Effects of Gas Pressure on the Size Distribution and Structure of Carbon Nanoparticles Using Ar + CH₄Multi-Hollow Discharged Plasma Chemical Vapor Deposition

“…To obtain information about radical generation, we measured the optical emission spectroscopy (OES) spectra of the discharges. Figure 4 shows a typical OES spectrum, in which un-ionized argon (Ar I), hydrogen (Balmer lines, H α at 656 nm, H β at 486 nm, and Hγ at 434 nm), hydrogen molecules (H 2 ), and CH* radicals (432.6 nm) are emitted from the discharge [24][25][26][27][28][29][30]. Figure 5 shows the pressure dependence of the emission intensity of CH* (432.6 nm).…”

Deposition of hydrogenated amorphous carbon films by CH4/Ar capacitively coupled plasma using tailored voltage waveform discharges

“…This trend is consistent with previous studies. 6,10) The decrease in H content and the increase in sp 3 fraction influence the increase in mass density of a-C:H films. Therefore, the mass density of a-C:H films is anticipated to be highest at a well balanced IBE of 200 eV for these two film compositions.…”

“…[1][2][3][4][5] a-C:H films for hard masks are mainly fabricated by PECVD using capacitively coupled plasmas (CCP), which ensures film uniformity at low temperatures. [6][7][8] One notable characteristic of CCP is DC self-bias voltage (V DC ), generated by the geometric asymmetry of the reactor. V DC makes electric fields that accelerate ions, thereby increasing ion bombardment energy (IBE).…”