Tuesday, February 23, 2021

Progress and future prospects of negative capacitance electronics: A materials perspective

NaMLab and TU Dresden, who has performed groundbreaking research on Ferroelectric hafnium oxide are also deep into Negtavie Capacitance devices for electronics to come. They have postulated 5 requirements for prospective ferroelectric materials that NC transistors need to fulfill to be useful for practical devices:

1. Robust ferroelectricity at 5 nm thickness and below
2. Compatibility with CMOS technology
3. Thermal stability on silicon
4. Conformal deposition on 3D substrates
5. Large electronic bandgap and conduction band offset to Si

Looking at the number 4 - ALD will come in handy. Enjoy the reading of their prospect paper below, which is open access.

Progress and future prospects of negative capacitance electronics: A materials perspective

Michael Hoffmann, Stefan Slesazeck, and Thomas Mikolajick

APL Materials 9, 020902 (2021); https://doi.org/10.1063/5.0032954

Negative capacitance in ferroelectric materials has been suggested as a solution to reduce the power dissipation of electronics beyond fundamental limits. The discovery of ferroelectricity and negative capacitance in the widely used class of HfO2-based materials has since sparked large research efforts to utilize these effects in ultra-low power transistors. While significant progress has been made in the basic understanding of ferroelectric negative capacitance in recent years, the development of practical devices has seen limited success so far. Here, we present a unique view of the field of negative capacitance electronics from the ferroelectric materials perspective. Starting from the basic principles of ferroelectric negative capacitance, we discuss the desirable characteristics of a negative capacitance material, concluding that HfO2-based ferroelectrics are currently most promising for applications in electronics. However, we emphasize that material non-idealities can complicate and in some cases even inhibit the design and fabrication of practical negative capacitance devices using HfO2-based ferroelectrics. Finally, we review the recent progress on experimental devices and give an outlook on the future direction of the field. In particular, further investigations of the microscopic structure of HfO2-based ferroelectrics are needed to provide an insight into the origin of negative capacitance in this material system and to enable predictive device design

Historic trend of the supply voltage Vdd and equivalent oxide thickness (EOT) scaling in commercial metal–oxide–semiconductor field-effect transistor (MOSFET) technologies. The black dashed line indicates the EOT limit given by the necessary SiO2 interface between the Si channel and the high-k material, and the red dashed lines indicates the minimum supply voltage due to the Boltzmann limit. HKMG: high-k metal gate. NC: negative capacitance.

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