Global model of a low pressure ECR microwave plasma applied to the PECVD of SiO₂thin films

Abstract

A global model for electronegative plasmas in a pressure range of 0.1–100 Pa is used to investigate the dissociation of the precursor in O2/SiCl(CH3)3 discharges. Microwave power is fed to the plasma by an annular waveguide ring with slotted line radiators on the inner side (SLAN) that is operated at 2.45 GHz. The modelling of the ECR plasma discharge and its application to the plasma enhanced chemical vapour deposition (PECVD) of silicon oxide films are reported. In the case of an oxygen discharge, theoretical values of the main plasma parameters (electron density and temperature and atomic oxygen population) are presented as a function of both pressure and electromagnetic power. The model results are compared with the experimental results obtained by optical emission spectroscopy, obtaining reasonably good agreement. The application of the model to the study of the PECVD of SiO2 film from O2/SiCl(CH3)3 mixtures has enabled us to determine that the fragmentation of the SiCl(CH3)3 molecule takes place mainly by electron impact dissociation, while the growth rate seems to be controlled by oxidation processes. Finally the influence of the precursor in the discharge has been studied. According to the model, in a first order approximation the insertion of the precursor causes an increase in the electron density due to the lower ionization threshold of the SiCl(CH3)3 molecule.

Optical refractive index and static permittivity of mixed Zr–Si oxide thin films prepared by ion beam induced CVD

“…Since the momentum transferred by 400 eV Ar + ions to the atoms at the film surface is more than twice that of 400 eV O 2 + ions [20], a possible explanation for this effect might be that there is a threshold momentum that prevents the incorporation of these groups to the films. Another explanation might be the fact that the relative amount of atomic O + with respect to O 2 + increase in a O 2 /Ar plasma with respect to O 2 plasma alone [21]. This way the chemical reactivity of the bombarding gas would be increased, producing more complete oxidation of the ZTB precursor.…”

Effects of negative ions on discharge characteristics of water plasma source for a miniature microwave discharge ion thruster

“…The global model assumes low voltage sheaths at the walls of cylindrical plasma of radius R and length L and predicts spatially averaged quantities in the bulk plasma, or the plasma density and the electron temperature, enabling the determination of discharge behavior in the plasma source. Being widely used, the global model [29][30][31] presented herein comprises the following equations that are solved self-consistently: (i) the particle balance equations for all charged species, except for the electrons, (ii) the energy balance equation, and (iii) the quasi-TABLE I. Chemical reactions of water vapor considered in the simulation with the rate constants used for the global model calculations.…”

Concepts, Capabilities, and Limitations of Global Models: A Review

“…It is important to know if the plasma is powered through a DC or AC drive, and if this is radio frequency (RF), or another waveform, and whether this is capacitively or inductively coupled, [14][15][16] or both. [17] Alternatives such a helicon drive [18] or electron-cyclotronresonance [19,20] are also possible.…”