Schematic of Nicholas Strandwitz work on atomic layer deposition

Schematic: Helping Technology Continue to Shrink

Nicholas Strandwitz, the Harold Chambers Junior Professor in Materials Science and Engineering, specializes in a thin-film growth process called atomic layer deposition (ALD).

Story by

Stephen Gross

Smartphones, laptops and other electronic gadgets wouldn’t be possible without transistors—semiconductor parts similar to a light switch—that are comprised of thin films of some tens of layers of atoms or molecules. Smartphones require more than a billion transistors, and computers require even more. 

Nicholas Strandwitz, the Harold Chambers Junior Professor in Materials Science and Engineering, specializes in a thin-film growth process called atomic layer deposition (ALD).
By fluctuating the temperature during the creation of films through thermally modulated ALD, Strandwitz is developing a new method of growing materials that could allow transistors to continue to shrink—and pave the way for the future of computing hardware.

Strandwitz’s project is supported by a CAREER Award from the National Science Foundation.

What the schematic shows:

  1. THIN FILMS. Transistors consist of films, parts of which are just 2.5 nanometers thick. The transistor itself is not much larger measuring at 10 nanometers and others even smaller.
  2. TEMPERATURE. Temperature is critical to the ALD process. It must be kept low enough—300 degrees Celsius and lower—so molecules don’t break apart on the surface of a silicon wafer and lead to a buildup of layers with the reaction no longer self-limiting.
  3. CRYSTALS. During conventional ALD, atoms arrange themselves into an amorphous, or “glassy,” state. Strandwitz wants to modify the process  and gently add heat, allowing atoms to rearrange themselves into a crystal, or ordered array.
  4. MONITOR. Strandwitz envisions using reflected high energy electron diffraction, or RHEED, to measure the arrangement of atoms. An electron beam attached to a custom ALD system, placed at a very shallow angle and bounced off the surface, hits an electron capture screen, where it glows or lights up. 

Story by Stephen Gross

Story by

Stephen Gross

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