Morphology Evolution of SiO₂ Films Deposited by Tetraethylorthosilicate/O₃ Atmospheric-Pressure Chemical Vapor Deposition on Thermal SiO₂

Abstract

A new structure of piezomotor using a flextensional coupler is proposed. Two longitudinal actuators and an elliptical shell constitute its frame. The basic structure and the operating mode are first presented. The coupling between a translation mode and a flexion mode generates an elliptic motion at shell tops. The design method based on a finite element model and an electromechanical equivalent circuit permits the structure dimensioning. Construction of motor prototypes indicates the reliability of the principle, a good agreement with design results and interesting motor performances. †

Modeling heterogeneity and memory effects on the kinetic roughening of silica films grown by chemical vapor deposition

“…Physically, the correlations of the noise arise from the coexistence of memory effects and surface heterogeneity during silica CVD growth. 18,19 It is important to stress that these new findings do not invalidate our previous results concerning the CVD silica growth evolution, rather they contribute to a more detailed understanding of such a complex growth process.…”

“…From these data it is evident that both sets of films have both active and passive ͑namely, less active͒ sites, and that the high-temperature set presents a lower concentration of active sites than the low-temperature set. On the other hand, it has been recently reported 18,19 for silica CVD films deposited from tetraethylorthosilicate ͑TEOS͒/ozone precursors that there exist memory effects during growth that influence the final film morphology, in particular, the film surface roughness. These memory effects are related to the existence of surface sites of different activities for deposition, and to the persistence in time of the activity properties for a given site on the substrate plane.…”

Modelling of silica film growth by chemical vapour deposition : Influence of the interface properties

“…Recently, it has been reported that the morphology of CVD silica films deposited by using TEOS as a precursor is largely determined by the existence of these two types of sites and by the presence of memory effects during the growth process [25,26]. Under these conditions the relative concentration of active and passive sites becomes determinant for the film growth.…”

Boundary Layer Chemistry Probed by in Situ Infrared Spectroscopy during SiO2 Deposition at Atmospheric Pressure from Tetraethylorthosilicate and Ozone

“…The chemical vapor deposition (CVD) of tetraethylorthosilicate [TEOS, Si(OC 2 H 5 ) 4 , also known as tetraethoxysilane] and ozone (O 3 ) has been used to deposit SiO 2 films suitable for use in VLSI (very large scale integration) device applications. − The TEOS/O 3 reaction system is unique in that the “as deposited” film profile can be varied from a conformal to flowlike step coverage depending on the initial ozone to TEOS concentration ratio. − The flowlike property is key to the deposition of high-quality dielectrics for shallow trench isolation with high aspect ratios and finds use in multilevel interconnect devices. Studies have focused on deposition at <400 °C to permit these deposition chemistries to be used with Al and Cu metallization schemes. , …”

“…[1][2][3] The TEOS/O 3 reaction system is unique in that the "as deposited" film profile can be varied from a conformal to flowlike step coverage depending on the initial ozone to TEOS concentration ratio. [4][5][6][7] The flowlike property is key to the deposition of high-quality dielectrics for shallow trench isolation with high aspect ratios and finds use in multilevel interconnect devices. Studies have focused on deposition at <400 °C to permit these deposition chemistries to be used with Al and Cu metallization schemes.…”