School Seminar Program

Memories taking resistive turn: Resistive switching as a non-volatile memory

Dinesh Venkatachalam

Dr Dinesh Venkatachalam
Electronic Materials Engineering

Growth in the use of portable electronic devices and embedded electronic systems has resulted in an increased demand for low-power, high-density non-volatile memory (NVM). However, current NVM technologies, based on charge storage, are rapidly approaching miniaturization limits. As a consequence, alternative technologies are required to meet future demands. Research over the past decade has led to the discovery of several new memory technologies, many in the category of Resistive Random Access Memory (ReRAM). Recently, the International Technology Roadmap for Semiconductors (ITRS) technical working groups have identified ReRAM as an emerging memory technology recommended for accelerated research and development. The intense interest in ReRAM technology is motivated by two major issues: First, scaling of NAND Flash technology will become excruciatingly difficult at the 16 nm technology generation, the cell size projected for year 2016 memory market and, second, one or more emerging ReRAM technologies will scale to the 8 nm technology generation. Additional incentives include their low cost-per-bit, low power operation, high endurance, and opportunity for 3D integration.

Resistive switching is a particularly interesting phenomenon in which the resistance of a dielectric film is switched between high and low resistance states by the application of suitable current-voltage (I-V) pulses, and is believed to result from the local breaking and reforming of conductive filaments produced in the film by an initial voltage stress. But its full realization is hampered by issues such as: a) lack of detailed knowledge about the forming and switching mechanisms, b) fluctuations in forming and switching voltages (reliability), and c) cumulative material and structural changes during repeated operation (endurance). Clearly, a detailed understanding of these processes and their dependencies are essential for future development and implementation of this technology. In this talk, I will discuss the resistive switching mechanisms in the technologically important high-k dielectrics, namely: hafnium oxide and hafnium silicates and highlight the use of ion-implantation to control the switching characteristics.

Dinesh graduated from BITS-Pilani, India in 2004 with a masters in materials engineering and then worked as a research and development engineer for TVS-Suzuki Motors India Ltd., before moving to RMIT University in Melbourne to pursue his PhD. Since completion in 2008 he has been working as a post-doctoral research fellow with Prof. Robert Elliman at the Electronic Materials Engineering Department.

Refreshments will be held in the tea room (around 5pm) after the seminar.  All welcome.

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