IBM Research and Caltech have announced a breakthrough that could lead to powerful but tiny computer chips, using DNA. The self-assembling origami structures could reduce chip production costs and resolve key semiconductor challenges as chip sizes drop below 22nm. The IBM and Caltech breakthrough with DNA appears to go beyond Moore's law. [ Read more ]

Research and the California Institute of Technology on Monday announced a scientific advancement that could make way for the semiconductor industry to build more powerful, faster, tinier, more energy-efficient computer chips. The breakthrough draws from lessons scientists have learned from DNA.

Together with Caltech's Paul W.K. Rothemund, IBM researchers reported an advancement in combining lithographic patterning with self-assembly. This method of arranging DNA origami structures on surfaces compatible with today's semiconductor manufacturing equipment could reduce production costs.

The breakthrough addresses key challenges in the semiconductor industry: developing lithographic technology for sizes smaller than 22nm and exploring new classes of transistors that employ carbon nanotubes or silicon nanowires. IBM's approach of using DNA molecules as scaffolding -- where millions of carbon nanotubes could be deposited and self-assembled into precise patterns by sticking to the DNA molecules -- may provide a way to reach sub-22nm lithography.

"The cost involved in shrinking features to improve performance is a limiting factor in keeping pace with Moore's law and a concern across the semiconductor industry," said Spike Narayan, manager of science and technology at IBM Research Almaden. "The combination of this directed self-assembly with today's fabrication technology eventually could lead to substantial savings in the most expensive and challenging part of the chipmaking process."

Relying on Nanostructures

As IBM explains it, this approach is useful because the positioned DNA nanostructures can serve as scaffolds, or miniature circuit boards, for the precise assembly of components -- such as carbon nanotubes, nanowires and nanoparticles -- at dimensions significantly smaller than possible with conventional semiconductor fabrication techniques. This opens up the possibility of creating functional devices that can be integrated into larger structures, as well as enabling studies of arrays of nanostructures with known coordinates.

Developed at Caltech, the techniques for preparing DNA origami cause single DNA molecules to self-assemble in solution through a reaction between a long single strand of viral DNA and a mixture of different short synthetic oligonucleotide strands. These short segments act as staples, effectively folding the viral DNA into the desired 2-D shape through complementary base-pair binding.

The short staples can be modified to provide attachment sites for nanoscale components at resolutions as small as six nanometers. In this way, DNA nanostructures such as squares, triangles and stars can be prepared with dimensions of 100nm to 150nm on an edge and a thickness the width of the DNA double helix.

The lithographic templates were fabricated at IBM using traditional semiconductor techniques to etch out patterns. Either electron beams or optical lithography were used to create arrays of binding sites of the proper size and shape to match those of individual origami structures. The key to the process was the discovery of the template material and deposition conditions to afford high selectivity so that origami binds only to the patterns of "sticky patches."

Surpassing Moore's Law

According to Charles King, principal analyst at Pund-IT, Moore's law has served the technology industry very well over the years, but when you reach the subatomic level and just can't go any smaller, innovation is the only answer.

"In the short term, what we are seeing from vendors like IBM and Intel is to find other ways to overcome the subatomic scalability problem and increase chip performance. Multi-threading and multi-core processors are the way the industry is moving right now," King said.

"What IBM is doing with this DNA-style technology is looking at next-generation -- or even generation after next -- technologies that will enable the company to continue scaling up performance in new and innovative ways."