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Thursday, February 24, 2011

Z-RAM: Zero Capacitor RAM

Hey Readers,

Just came across this article about a new technology being developed for a new type of a RAM, so wanted to put it up on my blog to spread the word. Actually, I read about it in January and had decided to put it up, but then again, I already confessed that I really am Quite lazy. Sorry, Anyway, here it is:

A Swiss Company, working with memory chipmaker Hynix Semiconductor, has introduced a design, which it says will be a cheaper, low-power replacement for the common computer memory known as dynamic RAM or DRAM.

Innovative Silicon, says that it has redesigned its zero capacitor RAM, or Z-RAM, so that it can be built on the same kind of wafers like ordinary DRAM. This is a big advance because its previous designs required specially designed wafers, and hence making it non-commercial and quite expensive.

The ZRAM does not require a capacitor, so the company estimated that its new design would be 25-30 percent cheaper as the critical features of memory drop below 40 nm in the next few years. Like the icing  on the cake, they ZRAM operates at voltages as low as 0.5-0.6 V, in line with what the future DRAM devices will require.

The results of the testing phase were reported by Hynix, South Korea at the 2010 symposium on VSLI technology in Honolulu. And they definitely do look good.

I am going to write a little about why this actually makes a difference and the reason it comes up in my blog. :)

DRAM stores a bit of memory -1 or 0- as the charge on a capacitor. The problem is that with the fast pace of miniaturization, the capacitors cannot be shrunk as fast as the transistors, as they should be able to hold a visible, or rather detectable, charge on them. And this is what has been giving several huge industrialists a run for their money.

Enter: ZRAM

Instead of a capacitor, a ZRAM relies on what's called a floating-body effect. By building a transistor in a layer of silicon deposited atop silicon dioxide- an insulator- you electrically isolate the transistor. When current passes through the transistor, some electrons create electron-hole pairs. The transistor's drain allows the extra extra electrons to leave, but the holes get stuck; thus leaving a positive charge. This can be read as a 1. This is the "floating" charge. Increasing the voltage on the transistor gate empties the holes through the source electrode, which can be read as a 0.

Fun part: With no more need of capacitors, the bit cells one need to be as the same size as Transistors, Which are getting smaller every year. ;)

Catch: Building the device on a silicon-on-insulator wafer, drove up the cost quite a bit.

Even Sweeter Icing: The company has figured out a way to make memories on bulk silicon. Instead of building the transistor on an insulating layer, they have made the transistor with the gate on top and source and drains on either ends. Innovative Silicon aligns the transistors vertically so that the gates are on either side and the junctions are at the top and bottom. That provides the same floating-body effect as the insulation. Added bonus, it fits with the industry move of a more 3D transistor.
Also, they new placements of the gates, make the transistor functional at voltages of 0.5V which they say is 50-75 percent lower than any floating-body memory device. The design therefore saves energy and makes the device compatible with the existing power supplies, keeping the cost down. They are paving the road map for 2020. So be ready to have RAMs of size 1 TB by then. ;)

BTW: Other companies such as Intel (the present leader) and Toshiba are also pursuing floating-body memory. ;);)

So get ready for an even better computing experience, readers.


Alpha over and out. ;)

2 comments:

  1. Great piece of information. And cool way to present it. :)

    Also, I had been waiting for this post since the day you mentioned you'll put it up.

    And, sorry for the late replies. I was out if you remember.

    Keep up the writing.

    ReplyDelete
  2. I am glad you liked it...

    I hall keep up the info distribution...;)

    ReplyDelete

Comments always welcome as they lead to betterment, but please keep them presentable, as other people read 'em too