Monday, November 22, 2004

On magnetoresistive random access memory (MRAM)

Jeff Young of Motley Fool has an interesting piece on the Magnetoresistive Random Access Memory (MRAM) of NVE.

It concludes:

This is the model of how a former penny stock like NVE becomes a darling of speculators. Take allegedly important patents and big name licensees who may never use the technology or produce a marketable product. Add a promotional CEO and mix in a self-styled "visionary" with a wide readership of speculators.

But dubious penny stocks have a habit of returning from whence they came. The truth is that everyone best positioned to understand NVE's technology and future business prospects -- Motorola or Cypress or even Baker -- has cashed out already. Investors who get caught in this trap have simply ignored the evidence before them.

Young also writes:

NVE has also enjoyed the sponsorship of a number of stock promoters, including most prominently the Forbes/Josh Wolfe nanotech newsletter, which first mentioned the stock in June 2003. Wolfe subsequently anointed it a "Nanosphere" play and the stock took off. Wolfe has shown panache as a self-promoter. Before he had made a single nanotech investment, he modestly heralded himself as one of the "true business visionaries of the nanotechnology sector."

Although Young does not mention specific patents of NVE, he states:

The highlight of what NVE calls its "watershed" MRAM patents is something known as a "one-transistor-per-bit read addressing scheme." This invention relates to the electrical circuitry supporting a memory cell, but has nothing specific to do with MRAM. Further, the claim is based on so much prior art that it's meaningless and unenforceable. The DRAM in your PC has relied on this approach for decades. Motorola did license technology from NVE in 1995, but this was before NVE even had these patents. Motorola pays NVE no fees today and has no reason to pay NVE royalties in the future. Meanwhile, Cypress Semi appears no closer than it has been to producing a commercially viable MRAM-based product. No other company with a major MRAM development program has licensed NVE's patents.

[Young notes that MRAM relies on magnetic tunnel junctions (MTJ). Separately, in conventional flash memory (not SRAM but EEPROM), there are two transistors which are separated from each other by a thin oxide layer. One of the transistors is known as a floating gate, and the other one is the control gate. The floating gate's only link to the row, or wordline, is through the control gate. As long as this link is in place, the cell has a value of 1. To change the value to a 0 one uses a process called Fowler-Nordheim tunneling, which alters the placement of electrons in the floating gate.]


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