PCM in the IoT Era

Recently, some heavy-weight technology company leaders have openly predicted an explosive rise of the Internet of Things (IoT, or IoE, Internet of Everything).  Although at its beginning, IoT market did not perform as predicted, now it seems certain that it is headed for accelerated growth.  With the advent of more advanced networking technologies such as the 5G wireless networks, the IoT can now indeed interconnect almost everything!  Undoubtedly, the scale of such technology transformation will be phenomenal and will create tremendous opportunities in the IT marketplace.

IoT, as an evolution to existing Internet technology, maintains the same hierarchical architecture: from the centralized Core networks to edge aggregation and finally to the access devices.  Massive amounts of data travels back and forth between all the connected nodes.

In fact, the main function of the IoT network is undoubtedly the transmission, storage and processing of the unimaginable amounts of data.  Up until now, all the information and data on the internet has been mostly created by, or at least, with help from humans.  But as IoT grows, the smart devices will generate much more machine-to-human and machine-to-machine data on the IoT.  According to IDC, the total amount of data generated by 2025 will be 79.4 zettabytes(ZB), which is 10²¹ Bytes.  Both the Processor and Storage technologies need to evolve to become both cheaper and efficient in order to handle the massive data generated by the billions of IoT nodes.

Data storage and processing can happen in the cloud, at the Core network, the edge network or in the device itself.   At the Core and Edge networks, PCM can be used as main memory to increase memory capacity at the same time reducing the access latency and cost.  PCM based storage products such as Intel’s Optane® DCPM have received much attention and welcomed by Data center operators, as the DCPM product have been shown to increase storage performance while reducing cost.

  With more data, along comes the processing of data, which is to turn the information contained in data into something useful to the human society.  Traditional Von Neumann processor architecture was never designed for such data intensive tasks, so new computing paradigms are being developed and deployed to process the so called “Big Data”.  A new architecture called Compute-In-Memory (CIM) has been of particular interest to the industry, in which some processor resides within the main memory to allow for extremely efficient data access.  This seemingly simple idea turns out to be very difficult to realize due to major technology limitations.  

When a processor needs to handle the data at close range, the most straightforward way is to build the processor and the memory on the same die.  However, all the current memory technologies do not allow this type of integration due to major process differences with the standard CMOS logic process. In this regard, PCM has a truly unique advantage, as the PCM manufacturing has been developed to seamlessly integrate into the most advanced CMOS process.  This allows PCM to be used as the main memory for In- or Near-Memory Computing, with powerful processors designed on to the same die.  Due to PCMs special properties, the data can be processed either using digital, analog, or even neuromorphic methods, all of which can be implemented using PCM technology, this makes PCM a significant new technology driver.  The integration of PCM and data processing technology will definitely enable and immensely benefit new ways of computing.

Lastly, the inter-connected devices can also benefit from PCM technology.  For on-device data storage and processing, other than replacing the traditional NOR/NAND flash storage, PCM can ensure top performance of these devices with the its NVM property and super-fast access time.  In fact, with near-DRAM performance, PCM can be directly interfaced to the processor bus of the embedded MCUs, simplifying the boot process, and enhance security as all critical data can be always hidden inside the MCU chip.

Another major benefit for using PCM in the IoT devices is the potential of “zero” standby-power.  When IoT devices goes into stand-by or sleep, the volatile memory components needs to be always powered on to keep the data alive.  When using the Non-volatile PCM, the entire chip can be put into deep power-down to consume very little power.  This is a significant power savings as for most battery powered devices, their stand-by power consumption can account for roughly 30 percent of its total power usage.

The Semiconductor technology advancement during the past 4 decades in undoubtedly the most important enablement factor that eventually led to the IoT evolution.  As Gordon Moore predicted since 1970 that the transistor performance roughly doubles every 2 years, while cost is reduced by half.  His prediction was based on observations from process development and MOS Transistor scaling theory.  

After over four decades of Moore’s law, which provided a crystal-clear path for Semiconductor Performance advancements, the MOS scaling “free-ride” seems to be nearing its end.  While some technologists still claim that there will be “More Moore”, there are also many others taking the “More than Moore” pathway.  

As we approach the impending Semiconductor Technology Crossroads, PCM is strongly poised to support the next leg of the technology race no matter where its headed.