CNTRENE®-material-based NRAM® devices

What is NRAM® technology?

NRAM® technology is applied to make advanced memory devices based on carbon nanotubes (CNTs). It revolutionizes the memory and the performance of many electronic devices including computers, tablets, cell phones, digital cameras, and more.

How do NRAM® devices work?

NRAM devices are resistive, non-volatile random access memory devices. In a simplified sense, the memory device is constructed with a CNT fabric sandwiched between two metal electrodes. The CNT fabric has two resistive states based on the state of the CNT fabric:

  1. If most of CNTs in the fabric are in contact with each other, resistance is low, and the state is “ON” or “1.”
  2. If the majority of CNTs in the fabric are NOT in contact with each other, resistance is high, and the state is “OFF” or “0.”

The two resistive states in the CNTs are stable, and so the NRAM device can act as a memory cell.

In the OFF state, the CNTs remain separated due to their mechanical stiffness. In the ON state, the CNTs remain in contact due to van der Waals forces between the CNTs. The resistive state is read by measuring the current/resistance between the top and bottom electrodes.

To switch an NRAM device between ON and OFF states, a voltage higher than the read voltage is applied to the electrodes. If the NRAM device is in the OFF state, the applied voltage causes electrostatic attraction between the CNTs and the device goes into the ON state. If the device is in the ON state, the applied voltage causes phonon excitations that separate the CNTs into the OFF state.

Features of NRAM® memory architecture:

  • High-density memory architecture (~50% reduction in memory area compared to NAND flash)
  • Fast 3-ns write, fast <20-ns read
  • Low power operation, non-destructive read
  • High >1012 cycle endurance demonstrated
  • High-temperature data retention
  • >10 years at 300°C from accelerated tests
  • No data loss at solder reflow conditions during board assembly
  • High scalability, currently NRAM® devices demonstrated at 15-nm node
  • Easy integration into fab processes, no exotic tools/processes required