Scientists have built a memory chip that is roughly the size of a white blood cell, about one-2,000th of an inch on a side.

Although the chip is modest in capacity — with 160,000 bits of information — the bits are crammed together so tightly that it is the densest ever made. The achievement points to a possible path toward continuing the exponential growth of computing power even after current silicon chip-making technology hits fundamental limits in 10 to 20 years.

The scientists, led by James R. Heath of the California Institute of Technology and J. Fraser Stoddart of the University of California, Los Angeles, will report their findings today in the journal Nature. As far back as 1999, Dr. Heath and Dr. Stoddart reported on aspects of their work , which included specially designed molecular switches and a novel technique for making ultrathin wires. The new work pulls the components into an integrated circuit.

“Our goal always was to develop a manufacturing technique that works at the molecular scale,” said Dr. Heath, a professor of chemistry. “It’s a scientific demonstration, but it’s a sort of a stake in the ground.”