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Deposition of carbon thin films using the dense plasma focus device
Author
Soh, Lee Yoong
Supervisor
Rawat, Rajdeep Singh
Abstract
In this work, the dense plasma focus (DPF) device was used to deposit amorphous diamond-like carbon thin films on silicon (100), glass and corning substrates using graphite fitted to the anode top. Substrates are placed at a distance of 120 mm from the anode (target). Other parameters include the number of focus shots (5, l0 and 15) and the filling gas pressures of neon (3.0, 4.0 and 5.0 mbar).
Shadowgraphy study is performed to investigate whether the current sheath is symmetrical during axial and radial phases as well as to outline the thin film deposition process. The shadowgraphy results showed that the current sheath of the DPF remains highly symmetrical even for the graphite fitted anode. Shadowgraphs also showed the graphite ablation and neon ionization wave front helping us in outlining the deposition process. The qualitative understanding of the deposition process was used in the analysis and interpretation of the results obtained from various characterization techniques.
XRD analysis showed that the deposited films are amorphous in nature. Thicknesses of the deposited films are found to range from 0.1 to 0.3 pm. FTIR analysis showed that the deposited films are hydrogenated with stretching modes of both sp' CH? and sp2 CH3.
Raman spectroscopy was used to determine the degree of diamond-like character (i.e. the sp3 content of the deposited films). Raman results showed that films deposited at the outermost position have higher sp3 content as compared with those deposited at the off-center position and the highest sp3 content obtained is about 85%.
Ultraviolet-Visible spectroscopy is used to estimate the optical band gap energy of the deposited films through Tauc plot method. It was found that films deposited at the outermost position have higher optical band gap energy than those deposited at the off-center positions. The estimated values range from 1.12 to 2.12 eV.
XPS results show the presence of nitrogen, oxygen and silicon besides carbon. The sp3 content obtained from XPS results matches within 80-90% with the IP/IG ratio calculations of Raman results for films deposited at outermost position but do not really matches with those deposited at the off-center position.
FSEM is used to study the surface morphology of the deposited films. It was found that films deposited at the outermost are smoother than those deposited at the off-center position. Also the films are of good quality as they are free from cracks and pinholes.
Hardness of the deposited films, obtained using the Nanoindenter, are found to be ranging from 3.2 to 13.6 GPa.
We have successfully deposited DLC thin films with the use of DPF device and this imply a potential use of this device as an alternative deposition method for producing DLC thin films at room temperature at relatively fast speed and at low cost.
Shadowgraphy study is performed to investigate whether the current sheath is symmetrical during axial and radial phases as well as to outline the thin film deposition process. The shadowgraphy results showed that the current sheath of the DPF remains highly symmetrical even for the graphite fitted anode. Shadowgraphs also showed the graphite ablation and neon ionization wave front helping us in outlining the deposition process. The qualitative understanding of the deposition process was used in the analysis and interpretation of the results obtained from various characterization techniques.
XRD analysis showed that the deposited films are amorphous in nature. Thicknesses of the deposited films are found to range from 0.1 to 0.3 pm. FTIR analysis showed that the deposited films are hydrogenated with stretching modes of both sp' CH? and sp2 CH3.
Raman spectroscopy was used to determine the degree of diamond-like character (i.e. the sp3 content of the deposited films). Raman results showed that films deposited at the outermost position have higher sp3 content as compared with those deposited at the off-center position and the highest sp3 content obtained is about 85%.
Ultraviolet-Visible spectroscopy is used to estimate the optical band gap energy of the deposited films through Tauc plot method. It was found that films deposited at the outermost position have higher optical band gap energy than those deposited at the off-center positions. The estimated values range from 1.12 to 2.12 eV.
XPS results show the presence of nitrogen, oxygen and silicon besides carbon. The sp3 content obtained from XPS results matches within 80-90% with the IP/IG ratio calculations of Raman results for films deposited at outermost position but do not really matches with those deposited at the off-center position.
FSEM is used to study the surface morphology of the deposited films. It was found that films deposited at the outermost are smoother than those deposited at the off-center position. Also the films are of good quality as they are free from cracks and pinholes.
Hardness of the deposited films, obtained using the Nanoindenter, are found to be ranging from 3.2 to 13.6 GPa.
We have successfully deposited DLC thin films with the use of DPF device and this imply a potential use of this device as an alternative deposition method for producing DLC thin films at room temperature at relatively fast speed and at low cost.
Date Issued
2003
Call Number
TK7871.15.F5 Soh
Date Submitted
2003