As we have discussed before, the current mainstream design for NAND flash memory faces difficulties as the transistors, used in construction, shrink below 20 nanometers (nm). When the chip density increases, cells can leak bits of data and cause errors in that data. Two emerging technologies, designed to possibly replace NAND one day, have been in the works for some time now. One of those technologies is magnetoresistive random-access memory (MRAM). MRAM stores data in each memory cell through a magnetic charge, combining the cache features of dynamic random-access memory DRAM with the non-volatile storage power of NAND. The independent manufacturer Everspin out of Chandler, Arizona has been leading the MRAM game and announced a partnership with GlobalFoundries, an investment company and the world’s second largest semi foundry, out of Abu Dhabi, to broaden their product line with smaller nm processes and capacity to increases up to 1Gb. There are many advantages of MRAM over NAND, most of which are centered on speed and power consumption and would give system builders other options for unique designs.
The other developing technology is resistive RAM, or RRAM. This type of memory is much denser than NAND while offering better performance through a wafer size that is half that of NAND. Instead of the standard Charge Trap Flash (CTF) process that uses transistors to store data bits, RRAM interconnects conductive filaments to store the data. To overcome electron leakage issues, Crossbar, a start-up in Silicon Valley and an industry leader in RRAM, issues a voltage range for each cell, and any cells outside of the range from -1 to +1 can store new data. To go even one step further, the company is on the cusp of entering the 3D storage market by incorporating 3D technology into its RRAM lines. This technology is much cheaper than die shrinking, so a stackable chip that is already much smaller than the current memory type is a huge step forward.
Despite all of the changing news in the NAND sector, one thing remains constant: we should expect big things in 2015 on this side of the memory market. With the total production value of electronic systems expected to grow to US$1.82 trillion by 2018, the 5.2% growth rate over last year will be heavily influenced by the ever-growing popularity of mobile devices, such as smartphones and tablets. What do almost all of those devices have in common? They depend on NAND flash as their main storage medium. Because of this relationship, we should expect to see a continued growth in NAND and increase in competition from manufacturers in the next calendar year.