Chengqiang Zhao

Field enhancement effect of metal probe in evanescent field

Field enhancement effect of metal probe in evanescent field, induced by using a multi-layers structure for exciting surface plasmon resonance (SPR), is analyzed numerically by utilizing two-dimensional (2D) TM-wave finite difference time-domain (FDTD) method. In this letter, we used a fundamental mode Gaussian beam to induce evanescent field, and calculated the electric intensity. The results show that compared with the nonmetal probe, the metal probe has a larger field enhancement effect, and its scattering wave induced by field enhancement has a bigger decay coefficient. The field enhancement effect should conclude that the metal probe has an important application in nanolithography.

Simulation and experiment on probe inducing surface plasmon resonance nanolithography system

The local field enhancement generates in the vicinity of the tip which has approached to surface plasmon resonance (SPR) region of the sample. The power of the local field enhancement could be utilized to pattern the sample, and this new lithography method is called probe inducing surface plasmon resonance nanolithography (PSPRN). Owing to the high energy density of local field enhancement and super-diffraction limiting character, PSPRN has the advantages of low power consumption and high resolution. The influence of various film parameters on SPR was simulated by eigenmatrix method in this paper. Through analysis and by comparison, glass ZF6, silver (Ag), silicon dioxide (SiO2) and silver oxide (AgOx) were selected as the materials for prism, metal layers, protecting layers and recoding layers respectively. A PSPRN experiment was implemented on an atomic force microscope (AFM). In the experiment, samples with single-layer, double-layer, and three-layer structures were researched. Holes of 100nm / 18nm, 75nm / 7nm and 195nm / 7.5nm (diameter/depth) were written into the three structures respectively. However, the result was not ideal with three-layer structure. The influence of diverse parameters on the size of lithography point has been analyzed, which could help providing the theory basis for improving experiment equipment.