Credit: Beaker via Wikipedia
Opposite sides of a quartz crystal resonator (via Wikipedia).
Researchers at the National Institute of Standards and Technology (NIST) have found a way to link measurements made by a device integral to microchip fabrication and other industries directly to the recently redefined International System of Units (SI, the modern metric system). That traceability can greatly increase users’ confidence in their measurements because the SI is now based entirely on fundamental constants of nature.
The device, a dime-size disk called a quartz crystal microbalance (QCM), is critically important to businesses that rely on precision control of the formation of thin films. Very thin: They range from micrometers (millionths of a meter) to a few tens of nanometers (billionths of a meter, or about 10,000 times thinner than a human hair) and are typically produced in a vacuum chamber by exposing a target surface to a meticulously regulated amount of chemical vapor that sticks to the surface and forms the film. The greater the exposure, the thicker the film.
Thin films are essential components in electronic semiconductor devices, optical coatings for lenses, LEDs, solar cells, magnetic recording media for computing, and many other technologies. They are also employed in technologies that measure the concentration of microbial contaminants in air, pathogens in the water supply, and the number of microorganisms that attach themselves to biological surfaces in the course of infection.
This animation demonstrates a new method for linking mass measurements made using quartz crystal microbalances directly to the SI. Ensuring the accuracy of these tiny sensors could provide a common re ..Support the originator by clicking the read the rest link below.
