Sandia Develops New Class of Dielectric Films

Researchers at Sandia National Laboratories announced they have developed an inexpensive and reliable class of dielectric films that could be used to enable programmable antifuses on integrated circuits (IC) at less cost and using easier-to-manufacture methods.

The new dielectric films, developed by Sandia researchers Scott Habermehl, Roger Apodaca and David Stein, enable single-mask-level sub 5 V write antifuses that are compatible with cutting-edge IC specifications. Antifuses -- nonvolatile, one-time programmable memories -- are used to permanently program ICs. People who need specially designed chips that are generally not available can use inexpensive chips made with the Sandia-developed dielectric film and permanently program them after fabrication, the researchers said.

This technology inexpensively enables such activities as post fabrication trimming, ROM programming, on-chip serial number identification, and data and program security. Chips with antifuse devices may also be used in high radiation environments or for long-term storage where flash memory would not be reliable.

“Antifuses have been around a long time,” says Paul Smith, who is involved in technology transfer at Sandia. “The new Sandia-developed film -- that ultimately is incorporated into computer chips with antifuses -- requires lower voltage and less real estate. This makes them more desirable than existing antifuses.” Smith said he hopes to attract outside companies to be Sandia partners who would commercialize the new film technology.

Current antifuse technologies rely on complex stacks of ultrathin films that are foreign to standard CMOS processes. These existing multistack solutions use write voltages significantly greater than 5 V, making existing antifuses incompatible with many leading-edge IC designs. The depositions of these films can also be difficult to control during production, resulting in a potential for poor yield and reliability issues, the researchers said.

“In addition to compatibility with state-of-the-art ICs, Sandia’s novel antifuse technology offers great flexibility toward where the antifuse can be placed in an IC,” said film co-inventor Habermehl. “It can readily be integrated into either the front end or the back end wiring.”

He said that the new dielectric technology enhances both process margin and device reliability, since it allows manufacturers to use thicker films for the antifuse elements, and can also use existing fabrication equipment and infrastructure without the need for costly, specialized and dedicated tooling and facilities.

Sandia is a Department of Energy National Nuclear Security Administration laboratory operated by Sandia Corp., a Lockheed Martin company. The lab has research and development responsibilities in national security, energy and environmental technologies and economic competitiveness. For more information, visit: www.sandia.gov