Paper PS-TuP3
Radical Nitriding of Silicon Surface Promoted by Surface Plasmon Resonance of Gold Nanoparticle Catalyst

Tuesday, October 22, 2019, 6:30 pm, Room Union Station B

In recent years, the catalytic effect of gold nanoparticles has attracted attention^{1, 2}. We have applied the catalytic property of gold nanoparticles to plasma surface reaction, and aim at the formation of a high-quality ultra-thin film by low damage nitriding by radical (R). This time, we compare the degree of nitridation by the presence or absence of ion irradiation (I), light irradiation (L), and the gold nanoparticle catalyst (C), respectively, and discovered the radical nitriding phenomenon by surface plasmon resonance of gold nanoparticles.

Gold is deposited for two minutes by electron beam evaporation on a SiO₂/Si(100) substrate in an ultra-high vacuum chamber.

Next, 30 mTorr of nitrogen plasma was generated in the attached chamber, and radicals (R) that had passed through a 30 line/inch SUS304 single mesh were irradiated to the sample for 5 minutes. When no light was applied, the sample surface was rotated 90 °.

The AFM images of gold nanoparticles produced by evaporation were compared under irradiation conditions of radicals, light, and ions.

The effect on the shape of gold nanoparticles increased in the order of RILC> RLC> RC.

It is clear that it is necessary to remove the ion irradiation in order to make the effect of the gold nanoparticles.

Next, surface atomic compositions by XPS were compared. The nitrogen ratio was not largely dependent on the irradiation conditions, but was relatively high in RI and RILC conditions where radical and ion irradiation occur simultaneously.

Comparing the XPS N1s spectrum, a peak near 398 eV of SiN is obtained strongly under the RLC condition where surface plasmon resonance can occur, and it can be imagined that a Si-N bond could be formed with the aid of the catalytic activity of Au nanoparticles.

When there is no light irradiation, the signal intensity of the Si-N bond is weak.

Also in the Si2p spectrum of XPS, the chemical shift between SiON and Si is small (3.6 eV) under the RLC conditions, which reflects the formation of the Si-N bond.

From the above, in the presence of light irradiation, it is considered that the catalytic activity of the Au nanoparticles is expressed by the effect of surface plasmon excitation, and the formation of the Si-N bond is promoted.

1. X. Chen, H.-Y. Zhu, J.-C. Zhao, Z.-F. Zheng, and X.-P. Gao, Angew. Chem. 120, 5433 (2008).

2. S. Bhaviripudi, E. Mile, S.A. Steiner, A.T. Zare, M.S. Dresselhaus, A.M. Belcher, and J. Kong, J. Am. Chem. Soc. 129, 1516 (2007).