One way to achieve faster and cheaper computer chips is by shrinking component sizes. For this, one research group have been looking at DNA.
Electronics manufacturers constantly hunt for ways to make faster, cheaper computer chips, often by cutting production costs or by shrinking component sizes. Now, researchers of Brigham Young University report that DNA, the genetic material of life, might help accomplish this goal when it is formed into specific shapes through a process reminiscent of the ancient art of paper folding.
Researchers now use DNA’s very small size, base-pairing capabilities and ability to self-assemble, and direct it to make nanoscale structures that could be used for electronics. The smallest features on chips currently produced by electronics manufacturers are 14 nanometers wide. That’s more than 10 times larger than the diameter of single-stranded DNA, meaning that this genetic material could form the basis for smaller-scale chips.
The problem, however, is that DNA does not conduct electricity very well. So the researchers use the DNA as a scaffold and then assemble other materials on the DNA to form electronics.
Nanoscale chips with “DNA origami”
The most familiar form of DNA is a double helix, which consists of two single strands of DNA. Complementary bases on each strand pair up to connect the two strands, much like rungs on a twisted ladder. But to create a DNA origami structure, researchers begin with a long single strand of DNA. The strand is flexible and floppy, somewhat like a shoelace. Scientists then mix it with many other short strands of DNA – known as “staples” – that use base pairing to pull together and crosslink multiple, specific segments of the long strand to form a desired shape.
However, the team isn’t content with merely replicating the flat shapes typically used in traditional two-dimensional circuits. With two dimensions, you are limited in the density of components you can place on a chip. If you can access the third dimension, you can pack in a lot more components.
The researchers have built a 3-D, tube-shaped DNA origami structure that sticks up like a smokestack from substrates, such as silicon, that will form the bottom layer of their chip. They have been experimenting with attaching additional short strands of DNA to fasten other components such as nano-sized gold particles at specific sites on the inside of the tube. The ultimate goal is to place such tubes, and other DNA origami structures, at particular sites on the substrate. The team would also link the structures’ gold nanoparticles with semiconductor nanowires to form a circuit. In essence, the DNA structures serve as girders on which to build an integrated circuit.
The researchers are currently testing the characteristics of the tubular DNA. They plan to attach additional components inside the tube, with the eventual aim of forming a semiconductor.
A conventional chip fabrication facility costs more than $1 billion, in part because the equipment necessary to achieve the minuscule dimensions of chip components is expensive and because the multi-step manufacturing process requires hundreds of instruments. In contrast, a facility that harnesses DNA’s knack for self-assembly would likely entail much lower start-up funding, he states. Nature works on a large scale, and it is really good at assembling things reliably and efficiently. If that could be applied in making circuits for computers, there’s potential for huge cost savings.