Artículos de revistas
Infrared studies on films of carbosilazane and siloxazane networks
Registro en:
Chemistry Of Materials. Amer Chemical Soc, v. 17, n. 18, n. 4685, n. 4692, 2005.
0897-4756
WOS:000231742600020
10.1021/cm0503139o
Autor
Trasferetti, BC
Gelamo, RV
Rouxinol, FP
de Moraes, MAB
Davanzo, CU
Institución
Resumen
The present work describes the effects of diluting hexamethyldisilazane (HMDSN) vapor either in pure argon or in oxygen-argon mixtures on the solid film deposited from the resulting plasma. Such a dilution provides a manner of incorporating controllable amounts of Si-O groups into the solid film. The characterization of the films investigated here was made by longitudinal and transverse optical (LO and TO, respectively) functions in the mid-infrared calculated through the Kramers-Kronig analysis of transmittance spectra. The infrared analysis showed that the films were formed by silicon-centered distorted tetrahedra of the following type: Si(CH3)(x)BU(2-0.5x), where 0 <= x <= 3 and BU stands for bridging unit. For the sample deposited in the absence of O-2 in the discharge, BU = CH2 and NH; for the samples deposited with an O-2 flow rate (f(O2)) of 2.5 and 10 sccm, BU = CH2, NH, and O; and for the sample deposited with f(O2) of 20 sccm, BU = NH and O. The Delta(LO-TO) for the Si-O asymmetrical stretching increased from 0 (f(O2) = 0 sccm) to 73 cm(-1) (f(O2) = 20 sccm), while for the Si-N asymmetrical stretching it decreased from 20 (f(O2) = 0 sccm) to 3 cm(-1) (f(O2) = 20 sccm). These observations signal an increase in the Si-O-Si network and a decrease in the Si-NH-Si network as the oxygen flow increased. An interesting conclusion drawn from our analysis of the Si-H stretching mode position and Delta(LO-TO) for the AS1 band is that the films deposited in the presence of O-2 are not structurally homogeneous, but have domains with different proportions of O bridges. 17 18 4685 4692