Researchers at Oak Ridge National Laboratory have developed a way to write on the nano scale using a scanning transmission electron microscope, STEM. The scientists at the Center for Nanophase Materials Sciences, CNMS - a DOE Office at ORNL, carried out the research. The team at CNMS weaved the aberration corrected sub-nanometer electron probe of the STEM through a Palladium solution (H2PdCl4) in a liquid cell to deposit the metal onto a Silicon microchip. The focused and controlled electron beam strikes the microchip and pure Palladium is deposted. Currently lithography is used to create patterns at the nano scale where the areas which are not to be imprinted with material are masked.
The liquid cell is made of a microchip with a Silicon Nitride membrane window through which the electron beam can pass. A sealed cell is required as it must be placed in the vacuum inside the electron microscope. Accurate control of the electron beam is critical to success of this nano lithography. The interface with the scan coils in the aberration corrected STEM is used to direct the electron beam position, speed, and dose. The current resolution of the “writing” is 40 nm. The researches at CNMS are working toward 10nm, current nanolithography can achieve this resolution.
“Direct-write liquid phase transformations with a scanning transmission electron microscope” Nanoscale, 2016,8, 15581-15588