Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Technology Stocks : Spansion Inc. -- Ignore unavailable to you. Want to Upgrade?

To: Joe NYC who wrote (2565)	11/15/2007 10:18:54 AM
From: Joe NYC	Read Replies (1) \| Respond to of 4590

Looks like Spansion has updated this page: Comparison with Flash Generally SONOS is very similar to Flash, but is, in theory at least, much easier to produce. Flash requires the construction of a very high-performance insulating barrier on the base leads of its transistors, often requiring as many as nine different steps, whereas the oxide layering in SONOS can be more easily produced on existing lines. Additionally, Flash leaks electrons through the insulator, a problem that grows worse as the size of the insulating barrier is reduced. Even with the introduction of new insulator technologies this has a definite "lower limit" around 7 to 12 nm, which means it is difficult for Flash devices to scale smaller than about 45 nm linewidths. SONOS, on the other hand, requires a very thin layer of insulator in order to work, making the base area smaller than Flash. This allows SONOS to scale to smaller linewidth, with recent examples being produced on 40 nm fabs and claims that it will scale to 20 nm.[1] The linewidth is directly related to the overall storage of the resulting device, and indirectly related to the cost; in theory, SONOS' better scalability will resulting in higher capacity devices at lower costs. Additionally, the voltage needed to bias the gate during writing is much smaller than in Flash. In order to write Flash, power is first built up in a separate device known as a charge pump, which multiplies the input voltage to between 9 V to 20 V. This process takes some time, meaning that writing to a Flash cell is much slower than reading, often between 100 and 1000 times slower. The pulse of high power also degrades the cells slightly, meaning that Flash devices can only be written to between 10,000 and 100,000 times, depending on the type. SONOS devices require much lower write power, typically 5 to 8 V, and do not degrade in the same way. SONOS does suffer from an unrelated problem, however, where electrons become strongly trapped in the ONO later and cannot be removed again. Over long usage this can eventually lead to enough trapped electrons to permanently set the cell to the "1" state, similar to the problems in Flash. However, in SONOS this requires on the order of a 100,000,000 write cycles, 1000 to 10,000 times better than Flash. [edit] History SONOS was first invented in the 1960s, but the semiconductor fabrication methodologies needed to develop it practically have not existed until recently.[citation needed] Philips is one of the groups working on SONOS devices[2], and have produced small 26-bit demonstrators with excellent lifetimes at a 120 nm linewidth. It is not clear if this research is ongoing, however, given the rapid advances in Flash technology that have led to very large gains in areal density. Other groups are also working on SONOS for more specialized tasks, notably military and space systems due to its excellent radiation hardness[3]. Spansion recently announced the development of SONOS flash memory using it's MirrorBit technology: biz.yahoo.com Joe