| AVS 64th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Tuesday Sessions |
| Session PS-TuP |
| Session: | Plasma Science and Technology Poster Session |
| Presenter: | Takeshi Kitajima, National Defense Academy of Japan, Japan |
| Authors: | T. Kitajima, National Defense Academy of Japan, Japan Y. Kariya, National Defense Academy of Japan, Japan T. Nakano, National Defense Academy of Japan, Japan |
| Correspondent: | Click to Email |
Gold nanoparticles show a catalytic features which depends on its size.
We tried to apply the catalytic property of the gold nanoparticles to a thin film processing under a plasma exposure. The catalysis enhanced process has a possibility of a low damage plasma processing that eliminate ion bombardments and charge trapping.
The example of the process is Si nitridation using low pressure nitrogen plasma.
Gold nanoparticles are self-assembled on a SiO2/Si(100) sample surface after the deposition of gold using an e-beam evaporator in an ultra high vacuum environment. After a 2 min. of gold deposition, hemispherical nanoparticles with the average width of 13.6 nm is formed. The number density of the nanoparticles is 6.0 e11 cm-2 and most of the surface area is covered with gold.
Inductive coupled plasma of 50 MHz excitation and 30 mTorr of nitrogen pressure is exposed to the sample with gold nanoparticles on the surface. After the plasma exposure, the surface morphology of the sample shows increased uniformity of the gold nanoparticle size. The nitridation degree of Si is examined with XPS.
Due to the N1s XPS signal ratio to the other component like Si2p, O1s, Au4f and C1s, nitrogen composition on the surface is evaluated.
The nitrogen composition of the samples with and without gold nanoparticles is 6.2 and 5.0 % after the plasma exposure of 15 s.
Even though the direct ion exposure to the SiO2 layer is inhibited by gold nanoparticles, Si sample is nitridated at similar rates with the aid of the catalytic effect of gold nanoparticles. The catalytic effect of the gold nanoparticles in this process is presumed to be the atomic transport of nitrogen atoms physisorbed on the nanoparticle surface to the underlined SiO2 interface and subsequent chemical reaction to form SiON.
The process with nanoparticle catalyst is expected to perform on various atomic layer synthesis like graphene functionalization and so on.