TY - JOUR
T1 - Differential voltage amplification from ferroelectric negative capacitance
JF - Applied Physics Letters
Y1 - 2017/
A1 - A.I. Khan
A1 - M. Hoffmann
A1 - K. Chatterjee
A1 - Z. Lu
A1 - R. Xu
A1 - C. Serrao
A1 - S. Smith
A1 - L.W. Martin
A1 - C. Hu
A1 - Ramamoorthy Ramesh
A1 - S. Salahuddin
KW - Capacitance
KW - Differential amplification
KW - Differential voltage
KW - Energy transfer
KW - External energy sources
KW - ferroelectricity
KW - negative capacitance
KW - Polarization state
AB - We demonstrate that a ferroelectric can cause a differential amplification without needing such an external energy source. As the ferroelectric switches from one polarization state to the other, a transfer of energy takes place from the ferroelectric to the dielectric, determined by the ratio of their capacitances, which, in turn, leads to the differential amplification. This amplification is very different in nature from conventional inductor-capacitor based circuits where an oscillatory amplification can be observed. The demonstration of differential voltage amplification from completely passive capacitor elements only has fundamental ramifications for next generation electronics. © 2017 Author(s).
PB - American Institute of Physics Inc.
VL - 111
N1 - cited By 15
ER -
TY - JOUR
T1 - Negative Capacitance in Short-Channel FinFETs Externally Connected to an Epitaxial Ferroelectric Capacitor
JF - IEEE Electron Device Letters
Y1 - 2016/
SP - 111
EP - 114
A1 - A.I. Khan
A1 - K. Chatterjee
A1 - J.P. Duarte
A1 - Z. Lu
A1 - A. Sachid
A1 - S. Khandelwal
A1 - Ramamoorthy Ramesh
A1 - C. Hu
A1 - S. Salahuddin
KW - Capacitance
KW - Capacitors
KW - Drain current
KW - Epitaxial ferroelectric
KW - Ferroelectric capacitors
KW - Ferroelectric devices
KW - Ferroelectric materials
KW - ferroelectricity
KW - integrated circuits
KW - MOSFET devices
KW - NC-FinFET
KW - negative capacitance
KW - Orders of magnitude
KW - Reconfigurable hardware
KW - Self-consistent simulations
KW - SPICE
KW - sub-60 mV/decade
KW - Transfer characteristics
AB - We report subthreshold swings as low as 8.5 mV/decade over as high as eight orders of magnitude of drain current in short-channel negative capacitance FinFETs (NC-FinFETs) with gate length Lg=100 nm. NC-FinFETs are constructed by connecting a high-quality epitaxial bismuth ferrite (BiFeO3) ferroelectric capacitor to the gate terminal of both n-type and p-type FinFETs. We show that a self-consistent simulation scheme based on Berkeley SPICE Insulated-Gate-FET Model:Common Multi Gate model and Landau-Devonshire formalism could quantitatively match the experimental NC-FinFET transfer characteristics. This also allows a general procedure to extract the effective S-shaped ferroelectric charge-voltage characteristics that provides important insights into the device operation. © 2015 IEEE.
PB - Institute of Electrical and Electronics Engineers Inc.
VL - 37
N1 - cited By 106
ER -
TY - JOUR
T1 - Negative capacitance in a ferroelectric capacitor
JF - Nature Materials
Y1 - 2015/
SP - 182
EP - 186
A1 - A.I. Khan
A1 - K. Chatterjee
A1 - B. Wang
A1 - S. Drapcho
A1 - L. You
A1 - C. Serrao
A1 - S.R. Bakaul
A1 - Ramamoorthy Ramesh
A1 - S. Salahuddin
KW - Boltzmann distribution
KW - Boltzmann equation
KW - Capacitance
KW - Capacitors
KW - Direct measurement
KW - Energy dissipation
KW - Epitaxial ferroelectric films
KW - Ferroelectric capacitors
KW - Ferroelectric devices
KW - Ferroelectric films
KW - Ferroelectric materials
KW - ferroelectricity
KW - Fundamental barriers
KW - Intrinsic energy
KW - negative capacitance
KW - New applications
AB - The Boltzmann distribution of electrons poses a fundamental barrier to lowering energy dissipation in conventional electronics, often termed as Boltzmann Tyranny. Negative capacitance in ferroelectric materials, which stems from the stored energy of a phase transition, could provide a solution, but a direct measurement of negative capacitance has so far been elusive. Here, we report the observation of negative capacitance in a thin, epitaxial ferroelectric film. When a voltage pulse is applied, the voltage across the ferroelectric capacitor is found to be decreasing with time - in exactly the opposite direction to which voltage for a regular capacitor should change. Analysis of this inductance -like behaviour from a capacitor presents an unprecedented insight into the intrinsic energy profile of the ferroelectric material and could pave the way for completely new applications. © 2015 Macmillan Publishers Limited. All rights reserved.
PB - Nature Publishing Group
VL - 14
N1 - cited By 302
ER -
TY - CONF
T1 - Understanding negative capacitance dynamics in ferroelectric capacitors
T2 - 2015 4th Berkeley Symposium on Energy Efficient Electronic Systems, E3S 2015 - Proceedings
Y1 - 2015/
A1 - A.I. Khan
A1 - K. Chatterjee
A1 - Ramamoorthy Ramesh
A1 - S. Salahuddin
KW - Capacitance
KW - Capacitors
KW - energy efficiency
KW - External resistors
KW - Ferroelectric capacitors
KW - Ferroelectric devices
KW - Ferroelectric switching
KW - ferroelectricity
KW - iron
KW - negative capacitance
KW - Resistors
KW - Semiconductor device measurements
KW - Semiconductor devices
KW - Single-crystalline
KW - Subthreshold characteristics
KW - Switches
KW - Transient analysis
KW - Transistor structure
AB - We investigate negative capacitance transients-the time period during ferroelectric switching when the voltage across a ferroelectric changes in a direction opposite to that of the charge-by constructing a simple series network of an isolated single crystalline ferroelectric capacitor and an external resistor. A study of negative capacitance dynamics in such a circuit reveals that the time scale of this phenomenon is controlled by the external resistor rather than by the material dependent intrinsic speeds. As a canonical approach for directly measuring ferroelectric negative capacitance, these experiments could guide the efforts to stabilize negative capacitance in a transistor structure for sub-60 mV/decade subthreshold characteristics as well as help assess negative capacitance response speed at technologically relevant dimensions. © 2015 IEEE.
JF - 2015 4th Berkeley Symposium on Energy Efficient Electronic Systems, E3S 2015 - Proceedings
PB - Institute of Electrical and Electronics Engineers Inc.
SN - 9781467385688
N1 - cited By 2
ER -