Memristors Ahoy
Next-gen memory semiconductor chips to take the place of DRAM and NAND flash are predicted to appear soon.
According to industry sources, companies in the industry are regarding 16 nm as the final stage of existing DRAM production processes. Under the circumstances, they are accelerating research on next-generation memory chips such as MRAM and ReRAM.
The limitation in microfabrication is because the improvement in the DRAM capacitor process has already reached its limit. “Any further microfabrication beyond 10 nm requires a reduction in capacitor size for smaller cells, but the thin film cannot be reduced in thickness any longer, and the adoption of high-k materials and suitable electrodes doesn’t seem to be possible anymore,” a local semiconductor company explained.
MRAM and ReRAM, which are drawing attention as alternatives to DRAM and NAND flash, are memory semiconductor chips driven based on a resistance effect. The former, which uses a magnetoresistance effect, has been developed in the form of STT-MRAM for magnetic tunnel junction (MTJ) current injections, mainly by SK Hynix and Toshiba, while the latter is characterized by on-off conversion depending on the magnitude of the voltage.
Both of them are nonvolatile, that is, capable of keeping their data even in the event of power cuts. In addition, each of them is dozens to hundreds of times faster and more durable than existing memory semiconductor chips. They have an internal structure much simpler than that of memory semiconductor chips and can allow two nanometer level microfabrication in theory, when an extreme ultraviolet (EUV) exposure system is employed.
Theoretical examination has already finished for these next-gen memory chips, and companies are now focusing on productivity and reliability enhancement. Equipment for optimal material selection and uniform and precise deposition are predicted to be made available in 2018 or later.