Grayscale nanolithography for 2D nanoelectronics

Grayscale structured surfaces with nanometer-scale features are used in a growing number of applications in optics and fluidics. Thermal scanning probe lithography achieves a lateral resolution below 10 nm and a vertical resolution below 1 nm, but its maximum depth in polymers is limited.

Now, researchers in the LMIS1, led by Jürgen Brugger, have developed an innovative combination of nanowriting in thermal resist and plasma dry etching with substrate cooling. Their method, recently published in the journal Microsystems & Nanoengineering, achieves up to 10-fold amplification of polymer nanopatterns into silicon dioxide (SiO₂₎ without proportionally increasing surface roughness.

Sinusoidal nanopatterns in SiO₂ with 400 nm pitch and 150 nm depth are fabricated free of shape distortion after dry etching. To exemplify the possible applications of the proposed method, grayscale dielectric nanostructures are used for scalable manufacturing through nanoimprint lithography and for strain nanoengineering of 2D materials. Such a method for aspect ratio amplification and smooth grayscale nanopatterning has the potential to find application in the fabrication of photonic and nanoelectronic devices.