Yale University, SRC develop next-generation DRAM

RESEARCH TRIANGLE PARK, USA: Semiconductor Research Corp. (SRC), the world's leading university-research consortium for semiconductors and related technologies, and Yale University researchers today announced they have developed a new DRAM cell using ferroelectric layers that could significantly increase the technological and market competitiveness for DRAM technology.

According to early findings, researchers have found a way to apply ferroelectric material to a DRAM cell, which eliminates the need for a storage capacitor found in conventional DRAM. Ferroelectric DRAM (FeDRAM) is a capacitor-less DRAM cell, with a cell structure very similar to a CMOS transistor, except that the gate dielectric is ferroelectric.

Compared to the conventional DRAM cell, FeDRAM offers simpler cell structure, improved scalability, a smaller cell size, orders of magnitude longer retention time, lower power consumption and the possibility of storing multi-bits per cell. Storing many bits of information in a single DRAM cell has not been done and is found primarily only in flash memories.

“There have been numerous research groups that have worked on similar ferroelectric device structures for non-volatile memory applications, but we believe this is the first innovative FeDRAM solution to an industry-wide problem,” said Professor T.P. Ma, Raymond John Wean Professor of Electrical Engineering at Yale University.

“If we are able to show through further research that FeDRAM indeed possesses the superb properties that we are seeing now, these advancements would produce meaningful cost and performance benefits to global DRAM makers and their customers.”

Reducing costs, increasing competitiveness
According to Professor Ma, the FeDRAM structure provides many benefits. FeDRAM allows a device to be programmed and erased by a gate voltage pulse. Since charge retention is at least 1,000 times longer than that in conventional DRAM, refreshing can be much less frequent.

Its circuit architecture is similar to flash memory, helping the manufacturability of the technology. The ability to use proven and existing fabrication facilities and equipment would make an industry transition to FeDRAM much easier.

“One key advantage of FeDRAM is its ability to scale,” said Kwok Ng, Director of Device Sciences at SRC. “Existing DRAM technology is not highly scalable due to its difficulty in maintaining an acceptable storage capacitance while reducing footprint. However, we see the potential for greater scalability with FeDRAM, extending the benefits well into the future.”

Researchers now are working toward being able to demonstrate FeDRAM cells, simple building block circuits and pathways for scaling. They believe that with SRC support and collaboration with other SRC member companies, FeDRAM will be ready to transfer to the industry for production in the foreseeable future.

SRC, NSF fund search for new transistors

SEMICON West 2009, SAN FRANCISCO, USA: Semiconductor Research Corp. (SRC), the world’s leading university-research consortium for semiconductors and related technologies, teamed with the National Science Foundation (NSF) to announce funding of $2 million in new supplemental grants for nanoelectronics research.

Researchers at six major NSF centers inside leading US universities will contribute to the goal of finding a replacement for the transistor -– the foundational building block of computing technology for decades -– and discovering a new digital switching mechanism using nanoelectronics innovation.

During his presentation at Semicon West, Dr. Jeff Welser, director, Nanoelectronics Research Initiative (NRI) for SRC, will express the importance of this research to the semiconductor industry, national competitiveness and the world.

“There is no question semiconductor technology has played a critical role in driving the global economy for the past half century,” said Welser.

“But the current transistor technology is rapidly reaching its limits, and long-term fundamental research is needed now to be ready for 2020 and beyond. The joint NSF-NRI projects put the country’s best minds together for a common goal –- finding a new device that will continue our leadership in the nanoelectronics era.”

Until recently, manufacturers were able to double the number of transistors on a chip at half the power for each transistor by shrinking them smaller and smaller in each new generation of semiconductor technology. However, it is becoming increasingly difficult to continue decreasing the power needed to turn the device off and on, making it difficult to continue the pace of product innovation from scaling alone.

“These investments in nanoelectronics align closely with NSF’s support for engineering and scientific research that furthers discovery,” said Dr. Lawrence Goldberg, senior engineering advisor at NSF. “We believe these grants, which support graduate students and postdoctoral associates, will create innovative technologies and help find a solution to this significant issue facing the semiconductor industry today.”

The joint NSF-NRI supplemental grants were awarded to teams at six NSF centers in nanoelectronics research:
* Network for Computational Nanotechnology, directed by Dr. Mark Lundstrom at Purdue University, working with Kaushik Roy and Supriyo Datta.
* Center for Integrated Nanomechanical Systems (COINS), a Nanoscale Science and Engineering Center, directed by Dr. Alex Zettl at University of California at Berkeley, working with Sayeef Salahuddin and Jeffrey G. Grossman.
* Center for Materials Science and Engineering, a Materials Research Science and Engineering Center, directed by Dr. Michael Rubner at Massachusetts Institute of Technology, working with Caroline Ross and Stuart Wolf (University of Virginia).
* Northwestern University Materials Research Center, a Materials Research Science and Engineering Center, directed by Dr. Monica Olvera de la Cruz at Northwestern University, working with Mark Hersam.
* Center for Advanced Materials Research, a Materials Research Science and Engineering Center, directed by Dr. William Curtin at Brown University, working with Rod Beresford.
* Center for Materials for Information Technology, a Materials Research Science and Engineering Center, directed and led by Dr. William Butler at the University of Alabama.

The NSF-NRI grants are for three years and are, in addition to the 18 grants made to NSF centers over the last three years, expanding and strengthening the commitment to the program.

Companies participating in NRI are GLOBALFOUNDRIES, IBM, Intel, Micron Technology and Texas Instruments. These companies will assign researchers to collaborate with the university teams.

Strong interactions with the NSF-supported centers will be instrumental in NRI reaching its goal of demonstrating the feasibility of novel computing devices in simple computer circuits during the next five to 10 years.