Uses-cases of an electron microscope

The physical properties of materials are closely connected to the type of atoms they are made of, how these atoms are arranged in space (their structure), and how the atoms are bonded to each other.

Often small details in these atomic arrangements, such as misplaced or missing atoms can have a very big impact on how materials perform.

Materials science

To make materials better, we need to be able to measure their structure and atomic arrangements. For this, we need tools that allow us to image them in extreme detail, down to a single atom.

The electron microscope provides us with just such a tool.

Transistors

We are now reaching a point where we can engineer materials with structures as small as just a few atoms across. As an example, let’s consider computer microchips.

Microchips are basically a complex network of electronic switches, known as transistors. If we carefully chain together these electronic switches we make circuits, which are able to undertake the complex calculations to allow your computer, phone or tablet to do its job.

A complex structure

Each transistor is itself a complex structure composed of multiple layers of material with different electrical properties. The very first transistors were large objects. As we have shrunk down the size of each transistor, we have been able to pack more switches into our computer chips.

This makes your phone or computer ever more powerful and benefits from longer battery life.

The evolution of the size of Intel’s transistors

The graph below shows the evolution of the size of Intel’s transistors from 2006 to 2019. The most recent generation of Intel processors use transistors around 10 nm in size: to put it perspective the size of these components is only about 30 atoms across or 100,000 times smaller than the diameter of a human hair.

When transistors are so small, even a tiny mistake in the manufacturing process or a single atom being in the wrong place in the crystal can affect the operation of the chip.

Electron microscopes are a key tool in imaging these chips right down to the atomic level to ensure the manufacturing process has been effective.

Two images of microchips are shown below:

^{Image credit: Leonardo Lari, York}

^{Image credit: Leonardo Lari, York}

Further applications of electron microscopy

Electron microscopes have a much broader range of uses than just electrical engineering. The microscopes here at York are used to investigate topics as diverse as:

• Watching chemical reactions as they happen allows us to design better catalysts for industrial processes
• Understanding how pollutants in the ocean affect the structure and strength of shells of scallops
• Studying new magnetic materials for use in advanced computer storage technologies
• Explaining why our bones are so strong by looking at their structure at the nanoscale

Electron microscopy is so important in fields ranging from biology to materials science that it has been the subject of two Nobel prizes. In 1986, Ernst Ruska was awarded half of the Nobel Prize in Physics for the design of the first electron microscope.

In 2017, the Nobel Prize in Chemistry was awarded jointly to Jacques Dubochet, Joachim Frank and Richard Henderson for the development of cryo-electron microscopy, a variation of TEM, used to determine the structure determination of biomolecules.