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New RAM technology developed

Posted by Hemos on from the fun-new-stuff dept.

Christopher Thomas writes "Tom's Hardware Guide had a link to this EE Times article, which describes a new type of RAM developed by Hitachi. It uses stored charge in what looks like a cleverly controlled floating gate to store data, as opposed to stored charge in capacitors in conventional DRAM. Hitachi says that it will be able to ship this in quantity reasonably soon. It looks reasonably compact, and will scale much more easily to smaller linewidths than standard capacitor-based DRAM cells. It's also faster, as you don't have the whole precharge/amplify readout cycle to deal with. "

2 of 43 comments (clear)

  1. Just a minor nit... by slew · · Score: 4

    As to the statement...

    "...It's also faster, as you don't have the whole precharge/amplify readout cycle to deal with. "

    This is probably not true. Precharge and amplify has less to do with nature of the memory cell,
    but are used to speed up the access time of a RAM device. Even today's fast static-RAMs use
    precharge and amplify circuits to speed things up. (DRAMs also use the sense amps to restore the
    capacitor charge on read cycles, but SRAMs usually don't need this function, but still have amps
    for speed).

    The precharge is to put the bit sense lines into a known state (as opposed to an unknown state).
    Once the bit cell starts driving the bit sense line the sense-amp, senses the small change from
    the known state and amplifies it. If you don't precharge, you have to wait a while for the data
    to stabilize. But if the bit sense lines are precharged to a known state, as soon as it starts
    to change one way or the other, the amp kicks in and bam!

    Also in a large (eg, Gbit arrays) the poor little super-small transistor that is attached to
    a bit of the memory in the middle the array has little hope of driving a big long piece of
    bit-sense wire out to the edge of the array without the help of an amplifier :-)

  2. Not exactly... but by slew · · Score: 5

    Although the fabrication technology for the chips inside the Sony PS2 hasn't been finalized,
    they are going to use what is called a hybrid process (logic and DRAM on the same die) to make
    an chip with embedded DRAM. Today's technology allows about 4Mbytes of DRAM to be put on a chip
    with the left over space used for logic. Yes, hybrid processes are a bit less efficient than all
    logic or all DRAM processes, but are catching up (about 1 generation behind)...

    Hybrid processes are currently the state of the art and allow cool things such as embedded DRAM.
    (which allow really wide busses and fast access) However, the memory is still capacitors and
    transistors, for standard DRAM not this wacky new stuff (but one of these days...).

    (oh, and -yes- I know what I'm talking about here... :)