TSMC turns logic FinFET into ReRAM

October 01, 2015 // By Peter Clarke
One of the more interesting papers scheduled for presentation at this year's International Electron Devices Meeting (IEDM) is about making a non-volatile memory device – together with its array select switch – from a leading-edge logic transistor.

As nature and engineering usually contrive to make things difficult for engineers this is seemingly a most unusually convenient development. And also potentially an industry-changing development.

The paper is set to show that hafnium-dioxide high-k dielectric material, which is used in the high-k metal gate (HKMG) of a 16nm FinFET, can also be used as a resistive memory device. It is likely that the dielectric is laid down as a separate ReRAM device adjacent to the transistor. The paper comes shortly after Intel and Micron announced a development in non-volatile memory technology dubbed 3D Xpoint (see Intel, Micron launch "bulk-switching" ReRAM).

However, at IEDM researchers from Taiwan's Tsing-Hua University and foundry chipmaker Taiwan Semiconductor Manufacturing Co. Ltd. are set to report on a 1kbit memory array made using TSMC's 16nm FinFET logic manufacturing process. It is dubbed a FinFET Dielectric memory, or FIND.

Paper 10.1 is: 1Kbit FinFET Dielectric (FIND) RRAM in Pure 16nm FinFET CMOS Logic Process.

Other virtues of the approach are that the FinFET can be used as the select transistor in the array and the dioxide-based resistive dielectric film for a storage node of the ReRAM cell. No additional masks or process steps are required, the paper's abstract states. The ReRAM cell size is 0.07632 square micrometers. This means that the memory, if it can show the desired read, read and endurance performance is intrinsically available as an embedded memory for SoCs. It could even allow a logic process to be used for making discrete memory ICs.

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