Deep-subwavelength lithography via graphene plasmons

We propose a scheme to overcome diffraction limit in optical lithography via graphene-plasmon (GP) interference. Taking advantage of the novel properties of GPs—tunability, low loss, and extremely large wave number—we can realize lithography with a resolution up to $1/100$ wavelength in arbitrary one- and even simple two-dimensional patterns. An advantage of this method is that it works in the linear optics regime and does not require either multiphoton absorption materials or strong intensity lasers.

Figure 1

(a) The diagram of the lithography scheme. The top gate can control the Fermi level of the monolayer graphene. GPs can be generated by the dielectric gratings. Dielectric 1 has permittivity ${\varepsilon }_1=2.0$ and dielectric 2 has permittivity ${\varepsilon }_2=2.0$. (b) The energy structure of the photoresist.

Figure 2

The Fermi level as well as the plasmonic wave number as a function of the voltage $V_{GD}$. Here, the vacuum wavelength of the plasmon is set to be ${\lambda }_0=8\mu \text{m}$ and the thickness $d$ of the bottom dielectric slab is set to be $10\text{nm}$.

Figure 3

(a) Two perpendicular located dielectric gratings couple two TM-polarized laser beams to the GPs. The period of the gratings is $a=720\text{nm}$, the width of the silicon rectangular is $b=36\text{nm}$, and the relative permittivity of the silicon is 12. Additionally, the distance between the gratings is $6\mu \text{m}$ and the height of the silicon rectangle is $150\text{nm}$. The field intensity distribution in the photoresist is $V_{GD}=1.73\text{V}$ in (b) and $V_{GD}=0.56\text{V}$ in (c).

Figure 4

The field intensity distributions with $V_{GD}=1.19\text{V}$ and incident angles (a) ${27}^{\circ }$ and (b) ${10}^{\circ }$.

Figure 5

The simulation of one-dimensional pattern.