Pioneering new research has unlocked a new technique called meniscus-mask lithography,which use water makes wires even more nano.The research was done by the chemist James Tour at the Rice University and graduate students.
The water formation is called a meniscus; it is created when the surface tension of a liquid causes it to curve. the curvy surface of water at its edge – can be an effective mask to make nanowires.Water is the key component in meniscus-mask lithography process to reliably create patterns of metallic and semiconducting wires less than 10 nanometers wide.
Meniscus-mask lithography :
The researchers have now made nanowires between 6 and 16 nanometers wide from silicon, silicon dioxide, gold, chromium, tungsten, titanium, titanium dioxide and aluminum. They have also made crossbar structures of conducting nanowires from one or more of the materials. Water’s tendency to adhere to surfaces went from an annoyance to an advantage when the Rice researchers found they could use it as a mask to make patterns. The water molecules gather wherever a raised pattern joins the target material and forms a curved meniscus created by the surface tension of water.
The meniscus-mask process involves adding and then removing materials in a sequence that ultimately leaves a meniscus covering the wire and climbing the sidewall of a sacrificial metal mask that, when etched away, leaves the nanowire standing alone.The process is promising for the semiconductor industry as it seeks to make circuits ever smaller. State-of-the-art integrated circuit fabrication allows for signal wires that approach 10 nanometers, visible only with powerful microscopes. These are the paths that connect the billions of transistors in modern electronic devices.
Better than current approaches :
Current approaches to making such tiny wires take several paths. Lithography, the standard method for etching integrated circuits, is approaching the physical limits of its ability to shrink them further. Bulk synthesis of semiconducting and metallic nanowires is also possible, but the wires are difficult to position in integrated circuits.
Tour said the process should work with modern fabrication technology with no modifications to existing equipment and minimal changes in fabrication protocols. No new tools or materials are needed.The Air Force Office of Scientific Research supported the research.
A paper on their technique has been published online by the American Chemical Society journal Nano Letters.
