Resistive Random Access Memory

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As Resistive Random Access Memory ( RRAM or ReRAM ) refers to a non-volatile electronic RAM-type of memory , which by changing the electrical resistance of a weakly conductive dielectric stores information. The memory cell of an RRAM, which can store the amount of information of one bit , consists of a normally non-conductive oxide in which artificial impurities are inserted, the electrical resistance of which can be switched between two extreme values by an electrical voltage applied during writing . The two resistance values ​​represent the two possible states logical 0 or logical 1 of one bit.

RRAM has been the subject of various practical development work at experimental level since around 2010; the first patents and research work on this technology date from the early 2000s. In 2013, Panasonic presented an 8-bit microcontroller with integrated RRAM with a volume of 64 kByte. As of 2017, however, apart from a few test applications, RRAM does not play a significant role in the field of semiconductor technology , as the prices are not competitive compared to other, similar memory cells such as flash memory .

Whether RRAM cells belong to the thematic area of memristors is controversial in the literature, as the functional definition of the memristor does not match that of an RRAM cell.

construction

The basis of RRAM is the effect that in the material of certain, normally electrically non-conductive dielectrics such as silicon dioxide (SiO 2 ) or hafnium dioxide (HfO 2 ), one or more electrically weakly conductive channels are permanently created during production by a partial discharge using a high-voltage pulse can be. These weakly conductive channels can be switched between the two states with high and low conductivity in the course of a write process, with different voltages being applied. The electrical conductivity of the duct is measured for the readout process .

RRAM cells are normally implemented as 1T1R cells, the abbreviation for a transistor and a resistor . The transistor serves as an amplifier and as an element for addressing the various memory cells in a memory array.

literature

  • Seungbum Hong, Orlando Auciello, Dirk Wouters (Eds.): Emerging Non-Volatile Memories . Springer, 2014, ISBN 978-1-4899-7536-2 .

Individual evidence

  1. ↑ Patent US6531371 : Electrically programmable resistance cross point memory. Filed June 28, 2001 , published March 11, 2003 , applicant: Sharp Laboratories Of America, Inc., inventor: Sheng Teng Hsu, Wei-Wei Zhuang. ‌
  2. ↑ Microcontrollers: 8-bit Low Power Microcomputers MN101L Series. Retrieved June 1, 2017 .
  3. ^ I. Valov, E. Linn, S. Tappertzhofen, S. Schmelzer, J. van den Hurk, F. Lentz, R. Waser: Nanobatteries in redox-based resistive switches require extension of memristor theory . In: Nature Communications . 4, 2013, p. 1771. bibcode : 2013NatCo ... 4E1771V . doi : 10.1038 / ncomms2784 . PMID 23612312 . PMC 3644102 (free full text).
  4. ↑ Mario Lanza: A Review on Resistive Switching in High-k Dielectrics: A Nanoscale Point of View Using Conductive Atomic Force Microscope . In: Materials . 7 (3), 2014, pp. 2155-2182.