Nov 5, 2020

[paper] TFT for Mixed Signal and Analog Computation

Eva Bestelink, Olivier de Sagazan, Lea Motte, Max Bateson, Benedikt Schultes, S. Ravi P. Silva,
and Radu A. Sporea
Versatile Thin‐Film Transistor with Independent Control of Charge Injection and Transport
for Mixed Signal and Analog Computation
Adv. Intell. Syst.. (2020) pp.1-9, DOI:10.1002/aisy.202000199 

Abstract: New materials and optimized fabrication techniques have led to steady evolution in large area electronics, yet significant advances come only with new approaches to fundamental device design. The multimodal thin-film transistor introduced here offers broad functionality resulting from separate control of charge injection and transport, essentially using distinct regions of the active material layer for two complementary device functions, and is material agnostic. The initial implementation uses mature processes to focus on the device’s fundamental benefits. A tenfold increase in switching speed, linear input–output dependence, and tolerance to process variations enable low-distortion amplifiers and signal converters with reduced complexity. Floating gate designs eliminate deleterious drain voltage coupling for superior analog memory or computing. This versatile device introduces major new opportunities for thin-film technologies, including compact circuits for integrated processing at the edge and energy-efficient analog computation.

Figure: Outcomes of separating control for injection and conduction shown via TCAD simulation. a) MMT transient response is much faster than conventional contact-controlled TFTs
b) A MMT with multiple, appropriately sized CG1 gates can function as a digital-to-analog converter (DAC) with CG2 providing an enabling, sampleand-hold (S/H) function. 

Acknowledgements: E.B. and R.A.S. contributed equally to this work. This work was partly supported through EPSRC grants EP/R511791/1 and EP/R028559/1 and Research Fellowship 10216/110 from the Royal Academy of Engineering of Great Britain. Device fabrication had been performed on the NanoRennes platform. The authors thank Dr. Brice Le Borgne for initial liaison and process discussions, Prof. John M. Shannon for on-going advisory meetings, Prof. Craig Underwood for reviewing the manuscript, Dr. David Cox and Mr. Mateus Gallucci Masteghin for assistance with the SEM images.

Nov 4, 2020

IEEE Germany EDS Chapter Elections

The IEEE Germany EDS Chapter has elected new ExCom members for the term 2020/2021. An exciting new leadership team has been built to establish EDS activities in Germany.

The new ExCom:
  • Chair: Mike Schwarz (TH Mittelhessen)
  • Vice Chair: Joachim Burghartz (Universität Stuttgart, IMS Chips)
  • Treasurer: Manfred Berroth (Universität Stuttgart)
  • Secretary: Sevda Abadpour (Karlsruhe Institute of Technology)
Further information is available online https://r8.ieee.org/germany-eds

[paper] Local Variability Evaluation on Effective Channel Length

Juan Pablo Martinez Brito, Graduate Student Member, IEEE, 
and Sergio Bampi, Senior Member, IEEE
Local Variability Evaluation on Effective Channel Length
Extracted with Shift-and-Ratio Method
IEEE TED, vol. 67, no. 11, pp. 4662-4666, Nov. 2020
doi: 10.1109/TED.2020.3017178

Abstract: In this study, the local variation of the effective channel reduction parameter (ΔL=Lm−Leff) of a MOSFET is extracted by means of the traditional shift-and-ratio (SAR) method. ΔL is then correlated with the threshold voltage difference (ΔVTH) between the device under test (DUT) and the reference device. It is demonstrated that there exists an optimal VG range for extracting reliable values of L through the SAR method. Statistical data analysis shows that for R≈ (Llong/Lshort)≈25, better results are achieved since the value of σ(ΔL) varies typically as the reciprocal 1/√ W. The test structure used in this work is a Kelvin-based 2-D addressable MOSFET matrix implemented in 180-nm bulk CMOS technology. The sample space is of 2304 devices divided into nine subgroups of 256 same size closely placed nMOSFETs.
Fig: (a) Full circuit micrograph (b) MOSFET Matrix structure (c) Zoomed-in view at DUTs 

Acknowledgment: The authors would like to thank and acknowledge the Brazilian public company CEITEC S.A. Semiconductors for the measurement infrastructure, the CAD Support Center (NSCAD) at Federal University of Rio Grande do Sul (UFRGS) for electronic design automation (EDA) support, and Silterra Inc. for the silicon prototyping services.

Nov 3, 2020

ASCENT project

Applications and Systems-driven Center for Energy-Efficient integrated Nano Technologies

The Mission of the ASCENT Center is to transcend the current limitations of high-performance transistors confined to a single planar layer of integrated circuit by pioneering vertical monolithic integration of multiple interleaved layers of logic and memory, by demonstrating beyond-CMOS device concepts that combine processing and memory functions, heterogeneously integrating functionally diverse nano-components into integrated microsystems and by demonstrating in-memory compute kernels to accelerate future data-intensive at-scale cognitive workloads.

Researchers at ASCENT pursue four areas of technology including three-dimensional integration of device technologies beyond a single planar layer (vertical CMOS); spin-based device concepts that combine processing and memory functions (beyond CMOS); heterogeneous integration of functionally diverse nano-components into integrated microsystems (heterogeneous integration fabric); and hardware accelerators for data intensive cognitive workloads (merged logic-memory fabric).

ASCENT is one of six research centers funded by the SRC’s Joint University Microelectronics Program (JUMP), which represents a consortium of industrial participants and the Defense Advanced Research Projects Agency (DARPA). Information about the SRC can be found at https://www.src.org/.

Src Jump Logo

ASCENT is a collaboration of the following Universities:

Logo Cornell

Logo Georgia Tech
Logo ND

Logo Purdue

Logo Stanford

Logo Colorado
Logo Minnesota

Logo Berkeley

Logo UC San Diego

Logo UC Santa Barbara

Logo UCLA Logo UT Dallas

Logo Wayne Logo Illinois Institute