Plasma-polymerized hexamethyldisiloxane films characterized by variable-energy positron lifetime spectroscopy

Variable-energy positron lifetime study of silicon-oxide films plasma deposited from hexamethyldisiloxane and oxygen mixtures

“…Note that the I 3 of the film prepared at an oxygen pressure of 6.2 Pa is very high (about 48%) and close to the value for conventional poly-(dimethylsiloxane) (44.2%) 30 and a plasma film of pure HMDSiO (47%) deposited at a high HMDSiO pressure of 4.7 Pa (at 100 W). 10 To study the thermal stability of the deposited films, three samples were annealed in a vacuum at 400°C and PALS measurements were made at room temperature (Table II). After annealing, the 3 and I 3 are both significantly reduced for films 6 (P O 2 ϭ 6.2 Pa) and 7 (P O 2 ϭ 7.9 Pa) whereas they are essentially unchanged for film 2 (P O 2 ϭ 1.3 Pa).…”

“…1). 10 After the air was removed from the HMDSiO (Tokyo Chemical Industry Ltd.) by vacuum freeze-thawing, the reactor was evacuated to a vacuum exceeding 0.01 Pa. Under steady flows of HMDSiO and oxygen, electrodeless glow discharge plasma was generated at an inductively coupled radio frequency (RF) of 13.56 MHz.…”

“…SiOOOSi bands around 920 -1200 cm Ϫ1 are well separated from SiO(CH 3 ) 3 and SiO(CH 3 ) 2 bands. To get more quantitative information on these bands, we evaluated the following quantities as previously 10 : the integrated absorbance I of absorption peaks in ␣() via I ϭ ͐ ␣()/d 12 ; peak position 0 25 ; and the width ⌫ of peaks in the imaginary part of refractive index k(), 25 which correlates with ␣() as ␣() ϭ 4k(). We calculated these quantities based on least-squares analysis by approximating SiO 2 bands at 920 -1200 cm Ϫ1 with one or two Gaussians.…”

“…[7][8][9] By choosing positron energies below a few kiloelecton volts with a variable-energy pulsed beam, we probed nanometer-size holes in thin carbonized silicon-oxide films plasma polymerized from pure hexamethyldisiloxane (HMDSiO) at different monomer flow rates (F) and discharge powers (W). 10 Good correlations were observed between o-Ps lifetime parameters in the films and the ratio of the discharge power to the monomer flow rate (W/F). 10 In this work, SiO x films were plasma deposited from HMDSiO mixed with O 2 and the effect of oxygen on the free volume and structure of deposited films was studied using variable-energy PALS.…”

“…10 Good correlations were observed between o-Ps lifetime parameters in the films and the ratio of the discharge power to the monomer flow rate (W/F). 10 In this work, SiO x films were plasma deposited from HMDSiO mixed with O 2 and the effect of oxygen on the free volume and structure of deposited films was studied using variable-energy PALS. Supplemental information on the chemical composition and structure was obtained by IR absorption spectroscopy and X-ray photoelectron spectroscopy (XPS).…”