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    As a replacement for flash memory, various technologies from nanocrystals to magnetic memory are considered, but developers still consider the memory as the most acceptable technology, the mechanism of which is based on a change in the phase state of the substance.
    The previous topic was “Intel: mass production of PRAM by the end of 2007.”
    In 2006, Intel together with STMicroelectronics demonstrated a memory chip based on technology that has been working on for 30 years. The first chip samples are called Alverston . AlverstonAlverston
    chips are based on material similar to that used to create optical disks ( chalcogenide glass ), and the principle of operation is based on phase transitions.
    For the first time, this technology became known more than 30 years ago, in 1970, when one of the founders of Intel, Gordon Moore , published an article on "phase memory" (Phase-change memory).

    The principle of operation of the "phase memory":



    Material - chalcogenide glass (GST), consists of germanium (Ge), antimony (Sb) and tellurium (Te). In the usual (cold) state, the material is an amorphous glassy structure with high electrical resistance (state 1). When exposed to high temperature (up to 600 degrees Celsius), the material crystallizes, it is important to achieve a temperature above the crystallization point, but below the melting point of the material, then the material will have a very low resistance (state 2). As a result of the phase transition, both the electrical characteristics and the optical ones (refractive index) change. This transition can be carried out in less than 5 ns (according to 2006 data).
    State 1 (poorly organized) is used to obtain a low level signal , and state 2 (rigidly structured) is used to obtain a high level signal .


    In February of this year, Intel announced a development to double the possible chip capacity based on phase transition technology. Previously, “phase memory” was realized by two states (described above), but researchers have shown that between the amorphous and crystalline states there are two more that can also be used to store information. By adding two bits to the cell Intel together with STMicroelectronics achieved a significant increase in chip performance. Intel had already mastered a similar trick with flash memory, in which more than one bit can be stored on a memory cell, so this step in the development of “phase memory” is not surprising.
    The study of “phase memory” has made significant progress over the past few years, and if a few years ago the transition to mass production did not look promising, now there is not a shadow of doubt about this.


    The main advantages and differences of the "phase memory":


    • the use of one’s own physical state, rather than an electronic charge, to store data
    • the possibility of using not only as DRAM and SRAM , but also as non-volatile memory,
    • lower power consumption
    • the ability to place more elements on the crystal,
    • high resistance to external influences,
    • durability (withstands about 100 million rewriting cycles, and also degenerates more slowly),
    • higher write and read speeds.


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