More reliable electronics for aircraft operating at altitudes where solar and cosmic radiation is encountered could be the outcome of microchips coated with nanotubes.
At altitudes of 30,000ft (9,150m) or more avionics in airliners and military aircraft are exposed to cosmic radiation levels hundreds of times greater than at ground level. This radiation degrades the etched silicon circuits and the chips malfunction, potentially shutting down avionics systems. The semiconductor industry has been aware of the issue of environmental radiation for years and the Aerospace Vehicle Systems Institute, a US industry/government technology body, has made countermeasures a high priority.
Nanotubes have a physical property that acts as an insulator against some of this radiation. These artificial carbon structures, which differ from graphite, are up to 1.4 nanometres in size and look like tubes. The approximately 1 nanometre thick coating that is now possible for conventional silicon chips could therefore provide some of the protection the devices need. Production prototypes of protected chips are to be manufactured over the next 12 months and offered to customers for use in aerospace applications. However, the company manufacturing them is having problems convincing people that the mass production of a chip with a 1 nanometre nanotube coating is already possible.
"It's difficult to explain to people that nanotechnology is really here," says Dr Brent Segal, co-founder and chief operating officer of Massachusetts-based nanotechnology company Nantero.
While the nanotube coating has applications for standard microchips used in airliner avionics, the process could also be used for future chips. Today's semiconductors have switching gates 130 nanometres wide. Semiconductors could have gates just 65 nanometres wide for higher transistor density and therefore greater processing power in two years' time. These could be used for high-altitude unmanned air vehicles' artificial intelligence systems for autonomous operation.
ROB COPPINGER / LONDON
Source: Flight International