Nirmaan Shanker

EECS Department, University of California, Berkeley

Technical Report No. UCB/

December 1, 2024

http://www2.eecs.berkeley.edu/Pubs/TechRpts/Hold/4f47fd3d797b84ddc4e4d851beaff38b.pdf

Over the past few decades, data generation from diverse sources, including the Internet of Things (IoT) and artificial intelligence (AI) applications, has grown exponentially. This surge in data has driven an unprecedented demand for hardware capable of supporting the extensive information processing required today. Consequently, the energy consumption of microelectronics has risen sharply and is projected to exceed 20% of global energy production by 2030. Addressing this challenge requires groundbreaking advances in materials and devices to develop more energy-efficient electronics. Ferroelectric materials, along with the negative capacitance effect, present a promising platform for achieving energy-efficient computing, memory, and energy storage solutions. The recent discovery of ferroelectricity in hafnium oxide (HfO2)-based systems—compatible with modern semiconductor fabrication processes—has rekindled interest in integrating ferroelectrics into current technologies.

In this dissertation, I integrate CMOS-compatible HfO2-ZrO2-based ferroelectrics within device structures designed towards realizing this goal. First, I demonstrate ultrathin (anti)ferroelectric stabilization in HfO2-ZrO2 films down to unit-cell thickness, showing the absence of a critical ferroelectric thickness in this material system. Next, I integrate ultrathin HfO2-based ferroelectrics into ferroelectric tunnel junctions (FTJs) toward achieving an embedded nonvolatile memory. I next investigate negative capacitance stabilization in ultrathin HfO2-ZrO2 heterostructures as a novel approach to equivalent oxide thickness (EOT) scaling in transistors, enabling further reductions in operating voltage beyond conventional high-κ dielectrics. Lastly, I demonstrate the negative capacitance effect in HfO2-ZrO2-Al2O3 superlattices, which, when integrated into 3D trench capacitors, achieve record-high energy and power densities for electrostatic energy storage. The breakthroughs presented in this work—ultrathin ferroelectricity and negative capacitance—within the CMOS compatible HfO2-ZrO2 material system pave a new path toward energy-efficient electronics. These advancements highlight the potential for innovative material integration to address the increasing energy demands of modern computing technologies.

Advisors: Sayeef Salahuddin

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BibTeX citation:

@phdthesis{Shanker:31552,
    Author= {Shanker, Nirmaan},
    Title= {HfO2-ZrO2-based Ferroelectricity for Next-Generation Energy-Efficient Electronics},
    School= {EECS Department, University of California, Berkeley},
    Year= {2024},
    Number= {UCB/},
    Abstract= {Over the past few decades, data generation from diverse sources, including the Internet of Things (IoT) and artificial intelligence (AI) applications, has grown exponentially. This surge in data has driven an unprecedented demand for hardware capable of supporting the
extensive information processing required today. Consequently, the energy consumption of microelectronics has risen sharply and is projected to exceed 20% of global energy production by 2030. Addressing this challenge requires groundbreaking advances in materials and devices to develop more energy-efficient electronics. Ferroelectric materials, along with the negative capacitance effect, present a promising platform for achieving energy-efficient computing, memory, and energy storage solutions. The recent discovery of ferroelectricity in hafnium oxide (HfO2)-based systems—compatible with modern semiconductor fabrication processes—has rekindled interest in integrating ferroelectrics into current technologies. 

In this dissertation, I integrate CMOS-compatible HfO2-ZrO2-based ferroelectrics within device structures designed towards realizing this goal. First, I demonstrate ultrathin (anti)ferroelectric stabilization in HfO2-ZrO2 films down to unit-cell thickness, showing the absence of a critical ferroelectric thickness in this material system. Next, I integrate ultrathin HfO2-based ferroelectrics into ferroelectric tunnel junctions (FTJs) toward achieving an embedded nonvolatile memory. I next investigate negative capacitance stabilization in ultrathin HfO2-ZrO2 heterostructures as a novel approach to equivalent oxide thickness (EOT) scaling in transistors, enabling further reductions in operating voltage beyond conventional high-κ dielectrics. Lastly, I demonstrate the negative capacitance effect in HfO2-ZrO2-Al2O3 superlattices, which, when integrated into 3D trench capacitors, achieve record-high energy and power densities for electrostatic energy storage. The breakthroughs presented in this work—ultrathin ferroelectricity and negative capacitance—within the CMOS compatible HfO2-ZrO2 material system pave a new path toward energy-efficient electronics. These advancements highlight
the potential for innovative material integration to address the increasing energy demands of modern computing technologies.},
}

EndNote citation:

%0 Thesis
%A Shanker, Nirmaan 
%T HfO2-ZrO2-based Ferroelectricity for Next-Generation Energy-Efficient Electronics
%I EECS Department, University of California, Berkeley
%D 2024
%8 December 1
%@ UCB/
%F Shanker:31552