OVONIC UNIFIED MEMORY(PCM)

VYSAKH V

MCA S2

NO:225

Classification of the Memory on the bases of Volatility of

information

o Volatile Memory

o Non-volatile Memory

What is a volatile memory?

Memory or storage whose contents are erased when the system's power is turned off or interrupted.

example: RAM

What is a non-volatile Memory

Non-volatile memory is the general name used to describe any type of memory which does not lose its information when power is turned off.

NVRAM(non volatile random access memory) is a subgroup of the more general class of non-volatile memory types.

The best-known form of NVRAM memory today is flash memory used in camera’s,scan devices and flash drives.

Ovonic unified memory(Phase-change memory)

Phase change memory or PCM is a term used to describe a class of non-volatile memory devices that uses the principle of reversible phase change in materials to store information.

PCM technology uses a class of material known as Chalocogenides, which are alloys containing

Germanium, Antimony and telluride.

In PCM technology uses the difference in resistivity between the two phases of the material.These phase change is induced by temperature.

Structural phases of Chalcogenide (Ge2Sb2Te5 )

Why chalcogenide glasses ? The crystalline and amorphous states of

chalcogenide glass have different electrical resistivity values, and this principle is used to store the data.

The amorphic, high resistance state is used to represent a binary 0, and the crystalline, low resistance state represents a binary 1 .

Chalcogenide is the same material utilized in re-writable optical media (such as CD-RW and DVD-RW). In those instances, the material's optical properties are manipulated, rather than its electrical resistivity, as chalcogenide's refractive index also changes with the state of the material.

PCM Storage element and operation

Phase-change memory

Advantages of PCM In one recent experiment, conducted by Manfred Vuttigom from

the Berlin University of Technology, scientists had PRAM cell with a diameter of 20 nanometers . In these cells, the transition between states occurred in just 16 nanoseconds - faster than any existing technology to date.

Fast read and write.

Lower power consumption.In mobile devices due to lower power consumption of this memory can increase battery life by 20%.

PRAM is a promising technology in the military and aerospace

industries where radiation effects make the use of standard non-volatile memories such as Flash impractical .

Simple manufacturing process.

Highly scalable.

High temperature resistance.

Application• OUM allows the rewriting of CD & DVDs • OUM has direct applications

o computers, o cell phones, o graphics-3D rendering, o GPS, o video conferencing, o multi-media, o Internet networking and interfacing, o digital TV, o telecom, o PDA, o digital voice recorders, o modems, o DVD, o networking (ATM), o Ethernet, and pagers.

Thank You!