Summary:

Integrated Magnetoelectronics has created a magnetic nonvolatile memory that has the potential to replace most types of memories in computers and digital devices, such as cellular phones. BMDO sought to replace the many types of memory and storage with a single all-metal memory chip. Called permanent random access memory (PRAM), the memory features increased speed, lower power consumption, higher shock resistance, and increased reliability. It is also radiation hardened. The company is gearing up to produce a PRAM that could replace portable memories now used in palmtop computers, digital cameras, and cellular phones. The company is in negotiations with Lockheed Martin to supply PRAM for military and space applications and is also planning to market the memory in the electrical industry for load management.

Technology Description:

IME has created a memory architecture that has the potential to replace most of the different types of memory and storage in computers and digital devices. Called permanent random access memory (PRAM), this technology is a nonvolatile, magnetic memory based on the giant magnetoresistance (GMR) effect. Increased speed, lower power consumption, elimination of rotating storage, and improved reliability are but some of the potential benefits. PRAM employs a magnetic memory driven by silicon logic. The anticipated all-metal construction may also lower production costs as well, when employed on an advanced device called SpinRAM..

PRAM and SpinRAM’s operation exploits a 1988 discovery in quantum mechanics, that of the GMR effect. Thin-film ferromagnetic layers, when coupled with nonmagnetic layers, can exhibit high or low resistance depending on how the magnetic moments of the material are aligned. According to Science magazine, “These materials can now be fabricated to produce significant changes in resistance in response to relatively small magnetic fields.”

IME’s GMR-based PRAM works essentially like the magnetic core memories that were once used in computers, but on a much smaller scale. It is constructed of two sets of electronically insulated lithographically patterned lines overlapping in a grid-like pattern. A storage charge, held in a nonmagnetic layer sandwiched between two ferromagnetic layers, is set or reset by a coincidence of currents in both grid lines.

The old magnetic core memories were nonvolatile, meaning they held the data after the power was shut off. However, that technology didn’t scale down very well. In a competitive market of ever-smaller memories, they were replaced by volatile transistor-based memories for fast memory (which can not hold data after the power is shut off), and by technologies like mechanical disk drives for storage. However, as the GMR effect increases the magnetic signal strength by an order of magnitude, GMR-based magnetic memory units can now be scaled to compete with semiconductor memories.

Several companies are exploiting the GMR effect in magnetic storage devices, both mechanical and solid-state. IBM’s GMR-based hard drive was introduced in late 1998. What separates IME’S use of GMR from IBM’s is that there are no moving parts in IME’s memory, as it is a solid state magnetic system. As a result, computers can retrieve data from PRAMs much more quickly than they can from disk drives. What separates IME’s GMR memory from other GMR-based RAM products being developed is its patented closed-flux structure. The lines are sandwiched by GMR-sensitive film, which minimizes magnetization creep, a slow form of memory loss that limits the versatility of other GMR-based memories. The closed-flux structure thus allows for an unlimited number of cycles, small drive currents, and miniaturization to the limits of lithography.

Another advantage of IME’s PRAM is its production cost, which, given economies of scale, could be lower than that of nonvolatile memories now used in portable electronics such as cell phones and digital recorders. PRAM could replace such memories as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash (a type of EEPROM that can accept large blocks of data at a time). To fabricate a magnetic memory semiconductor requires only about six masking steps, as opposed to the more than 20 that those memories require. Fewer masking steps are an important feature in the all-metal SpinRAM, as it simplifies production, lowering manufacturing cost.

MDA Origins:

In 1998, IME completed a BMDO SBIR Phase II on Unified Memory Architecture. BMDO sought to replace the many types of memory in its computer devices with a single type of all-metal memory chip. The technology also employs research from a BMDO Phase I for an improved method of trimming thin film resistors, and a 1993 Phase I that investigated magnetic mass memory without mechanical motion.

Spinoff Applications:

PRAM’s speed, radiation hardness, random access, substantially unlimited read/write cycles, and low power insure potential competitiveness in all memory/storage markets.

The most immediate market would be for flash memory replacement. The market for flash memory is the most rapidly growing of all the nonvolatile memory markets (sales totaled $5 billion in 1998). Flash memory cards are used in such devices as palmtop computers, digital cameras, and cell phones. PRAM’s random access capability eliminates the need for adjacent EPROM memory, which is now required to run flash memory. And, unlike flash, PRAM has unlimited read/write cycles. In addition, IME’s PRAM could serve as a replacement for other nonvolatile memories as well, including ROM, EPROM, and EEPROM.

More long term possibilities for PRAM include potentially replacing most other forms of computer memory as well. With competitive cost through achieved economies of scale, PRAM can replace dynamic random access memory (DRAM), offering an equivalent speed plus the major additional feature of nonvolatility. In place of transistors are IME’s patented magnetic-based transpinnorsTM which can hold a charge after the power has been shut off. PRAM can replace mechanical disk drives, once scalability issues are resolved. Advantages here include simplified memory architecture as well as the elimination of moving mechanical heads, both of which would considerably speed performance. A PRAM would also resist shock and vibration better than disk drives.

In addition to replacing memory in computers, PRAM can address the memory needs of most portable devices, such as cell phones. Many cell phones now require flash, EEPROM, and dynamic random access memory (DRAM) memories for advanced features such as address storage. This collection can be replaced by a single PRAM. In addition to simplicity, another advantage to using PRAM is that it is radiation hardened. Unlike semiconductor-based components, PRAM devices are not vulnerable to radioactive interference, making them viable for space and satellite use without large lead shielding.

Commercialization:

At present, the company is working on 8-, 16-, and 64-kilobyte prototype PRAM devices. By the end of 1999, the company plans to test a one megabyte PRAM that would act as a replacement for flash cards, with 2- and 4-megabyte PRAMs to follow shortly thereafter. In 2001, the company plans to have a 256-megabyte PRAM, which would make it competitive with the commercial DRAM used in computers.

In addition to building off-the-shelf components that can be used in computers and portable devices, IME also hopes to tailor PRAM cards to specific markets. One field IME is pursuing is load management devices for electric utility companies, where microchip-driven devices can regulate the use of electricity by appliances. The company is also in negotiations with Lockheed Martin to provide memory for its radiation-hardened computer chip, which will be used in areospace and satellite applications.

Company Profile:

Integrated Magnetoelectronics is based in Berkeley, CA. It has been in operation since 1989, and was incorporated in 1993. It has eight full- and part-time employees in its Minneapolis R&D lab and an additional three in Berkeley. The company’s mission is to become a leader in the field of solid-state magnetoelectronics.

Contact Information:

Dr. Richard Spitzer, President
Integrated Magnetoelectronics
1214 Oxford Street
Berkeley CA 94709
Tel:510-841-3585
Fax:510-841-2405