Nanoscale programming of ferroelectric thin films using Ultra-low Voltage E-beam Lithography*

The ability to control ferroelectric domains at nanoscale dimensions is essential for ferroelectric-based device fabrication, especially with atomically-thin films, and its impact extends further to nanoelectronics. Using direct irradiation from an ultra-low voltage electron beam¹, nanoscale ferroelectric domains can be patterned on a pre-poled, out-of-plane polarization Al_0.9B_0.1N thin film on demand. Atomic-force microscope (AFM) and piezoelectric-force microscope (PFM) characterizations are carried out showing clear patterned domains with less than 50 nm resolution. It has been demonstrated previously that ULV-EBL can pattern LaAlO₃/SrTiO₃ heterostructures through the van der Waals (vdW) layers.  Creating high-resolution ferroelectric patterns in proximity to vdW heterostructures can be used to create voltage-programmable nanostructures, taking advantage of the large (~10¹⁵ cm^-2) switchable ferroelectric polarization. 

1. Appl. Phys. Lett. 117, 253103 (2020)