Extending Moore’s Law using nuclear fusion

We recently looked at a technique that could help extend Moore’s Law by using DNA molecules as scaffolding to pack more power and speed into computer chips. Now researchers from Purdue University and the U.S. Department of Energy's Argonne National Laboratory are working to achieve the same result by adapting the same methods used in fusion-energy research to create extremely thin plasma beams for a new class of 'nanolithography'.

Current technology uses ultraviolet light to create the fine features in computer chips in a process called photolithography, which involves projecting the image of a mask onto light-sensitive material, then chemically etching the resulting pattern. Unfortunately, this technique is reaching its limit, so the research team is looking at ways of creating beams with narrower wavelengths.

The researchers are examining two different techniques to create the plasma beams, which generate "extreme ultraviolet" light having a wavelength of 13.5 nanometers, less than one-tenth the size of current lithography. One approach uses a laser while the other 'discharge-produced' method uses an electric current.

In either case, only about one to two percent of the energy spent is converted into plasma, so the researchers are working to improve the efficiency of both methods to reduce the energy requirements. Critical to the research is a computer simulation, called HEIGHTS (high-energy interaction with general heterogeneous target systems), which simulates the entire process of plasma evolution.

In experimental fusion reactors, magnetic fields are used to keep plasma-based nuclear fuel from touching the metal walls of the containment vessel, enabling the plasma to be heated to the extreme temperatures required to maintain fusion reactions. Simulations of laser-produced plasma beams carried out using HEIGHTS match data from laboratory experiments recently built at Purdue, which tells the researchers they are on the right track.

"The computer simulations tell us how to optimize the entire system and where to go next with the experiments to verify that," said Ahmed Hassanein, the head of Purdue's School of Nuclear Engineering.

The research teams findings will be detailed in the October-December 2009 issue of the Journal of Micro/Nanolithography, MEMS, and MOEMS.