SAN FRANCISCO — IBM scientists are reporting progress in a chip-making technology that is likely to ensure the shrinking of the basic digital switch at the heart of modern microchips for more than another decade.

The advance, described in the journal Nature Nanotechnology on Sunday, is based on carbon nanotubes, molecules that have long held promise as an alternative material to silicon from which to create the tiny logic gates that are used by the billions to create microprocessors and memory chips.