Towards logic functions as the device

Abstract

-This paper argues for alternate state variables and new types of sophisticated devices that implement more functionality in one computational step than typical devices based on simple switches. Elementary excitations in solids enabling wave interactions are possible initial candidates to create such new devices. The paper focuses on magnon-based spin-wave-logic functions (SPWF) and presents high fan-in majority, weighted high fan-in majority, and frequency-multiplexed weighted high fan-in majority devices as initial SPWFs. Experiments proving feasibility are also shown. Benefits vs. scaled CMOS are quantified. Results show that for 128 or larger inputs even a 2.5µm SPWF carry-look-ahead adder implementation is faster than the 45nm CMOS version. The 45nm SPWF adder is expected to be significantly faster across the whole range of input widths. In particular, the 45nm SPWF CLA adder is estimated to be at least 77X faster than CMOS version for input widths equal to or greater than 1024. A second example of a counter circuit is presented to illustrate the considerable reduction in complexity possible vs. CMOS.

Magnonic Logic Devices

“…Figure 8 shows the schematics of the four-terminal spin wave device used as a prototype for the MAJ gate [56]. The material structure from the bottom to the top consists of a silicon substrate, a 300nm thick silicon oxide layer, a 20nm thick ferromagnetic layer made of Ni 81 Fe 19 , a 300nm thick layer of silicon oxide and the set of fi ve conducting wires on top.…”

“…The latter offers an additional degree of freedom for logic circuit construction. Besides that, the utilization of spin wave interference is effi cient for building high fan-in devices, which is a signifi cant advantage over the transistor-based circuits [56]. Overall, magnonic Boolean logic circuits can be constructed with a fewer number of elements that it is required for CMOS counterparts [60].…”

“…0.6 MV/m for Ni/PMN-PT). Such a relatively weak electric fi eld promises an ultralow energy consumption required for magnetization switching [29]. Synthetic multiferroics has been used for spin wave excitation/detection and have shown a reliable operation at room temperature [30].…”

N³ASICs: Designing nanofabrics with fine-grained CMOS integration

“…For example, spin waves [28], QCAs [6], carbon nanotubes [14], semiconductor nanowires [13] [11] etc are under investigation as potential replacements for CMOS. However, reliable manufacturing of integrated nanosystems incorporating these novel nanodevices continues to be challenging.…”

Regular 2D NASIC-based architecture and design space exploration

“…A number of different fabrics and architectures are currently under investigation, for example NanoPLA [3], CMOL [1], FPNI 3 [2], NASIC 4 [4]. They are based on a variety of devices such as field effect transistors (FET) [5], spin-based devices [6], diodes, and molecular switches [7]. All these fabrics include some support in CMOS: some like FPNI would move the entire logic into CMOS, others, like NASIC, would only provide the control circuitry in CMOS.…”