Related Experiment Video
Updated: Jul 24, 2025
09:49
In Situ Transmission Electron Microscopy with Biasing and Fabrication of Asymmetric Crossbars Based on Mixed-Phased a-VOx
Published on: May 13, 2020
4.1K
Trade-off between Gradual Set and On/Off Ratio in HfO-Based Analog Memory with a Thin SiO Barrier Layer
Fabia F Athena1, Matthew P West2, Jinho Hah2
1School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
ACS Applied Electronic Materials
|July 3, 2023
Summary
Adding a barrier layer to HfO2-based synaptic devices improves resistance control during set operations. However, this modification results in a reduced on/off ratio, impacting analog memory applications.
Area of Science:
- Materials Science
- Electrical Engineering
- Computer Engineering
Background:
- Hafnium oxide (HfO2)-based synapses are promising for in-memory and neuromorphic computing.
- Resistance switching in these devices relies on oxygen vacancy movement, often exhibiting abrupt changes limiting analog memory use.
Purpose of the Study:
- To investigate the effect of inserting AlO2 or SiO2 barrier layers on the resistance switching characteristics of HfO2-based synapses.
- To improve the controlled resistance change of HfO2 synapses for better analog memory performance.
Main Methods:
- Fabrication of HfO2-based synaptic devices with and without AlO2 or SiO2 barrier layers at the bottom electrode/oxide interface.
- Electrical characterization to analyze resistance switching behavior, focusing on the set operation and on/off ratio.
- Finite element modeling to understand the impact of barrier layers on oxygen vacancy migration and conductive filament rupture.
Main Results:
- The HfO2/SiO2 devices exhibited more controlled resistance changes during the set operation compared to bare HfO2 devices.
- The on/off ratio of HfO2/SiO2 devices (approximately 10) was lower than that of HfO2/AlO2 and HfO2 devices.
- Finite element modeling indicated that slower oxygen vacancy migration in HfO2/SiO2 devices leads to a narrower filament rupture region, resulting in a lower high resistance state and reduced on/off ratio.
Conclusions:
- Slowing oxygen vacancy migration using barrier layers in HfO2-based synapses enhances control during the set operation.
- The trade-off for improved set control is a reduction in the overall on/off ratio, which needs consideration for analog memory applications.
Related Concept Videos
01:25MOS Capacitor
851
A Metal-Oxide-Semiconductor (MOS) capacitor is a fundamental structure used extensively in semiconductor device technology, particularly in the fabrication of integrated circuits and MOSFETs (metal-oxide-semiconductor field-effect transistors). The MOS capacitor consists of three layers: a metal gate, a dielectric oxide, and a semiconductor substrate.
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
851
01:24Metal-Semiconductor Junctions
395
The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
395
01:22Biasing of FET
324
Biasing a Junction Field Effect Transistor (JFET) is crucial for setting operational parameters and ensuring efficient functioning in electronic circuits. JFETs are characterized by using a single carrier type in N-channel or P-channel configurations, where the channel is surrounded by PN junctions. These junctions are central to the device's ability to control current flow.
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the...
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the...
324
01:22MOSFET: Enhancement Mode
389
Enhancement-mode MOSFETs are pivotal components in electronics, distinguished by their capacity to act as highly efficient switches. They are part of the larger family of metal-oxide Semiconductor Field-Effect Transistors (MOSFETs). They are available in two types: p-channel and n-channel, each tailored to specific polarity operations.
In their basic form, enhancement-mode MOSFETs are typically non-conductive when the gate-source voltage (Vgs) is zero. This default 'off' state means no...
In their basic form, enhancement-mode MOSFETs are typically non-conductive when the gate-source voltage (Vgs) is zero. This default 'off' state means no...
389
01:27Biasing of Metal-Semiconductor Junctions
284
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
284
01:17Characteristics of MOSFET
423
Metal-oxide-semiconductor field-effect Transistors, or MOSFETs, play a critical role in electronic circuits. They are primarily utilized for amplifying and switching signals.
Various vital parameters influence their functionality, which is crucial for theory and electronics applications. First, channel dimensions, precisely length, and width, are pivotal. The size of these channels affects the transistor's ability to carry current and switching speeds; shorter channels typically enable...
Various vital parameters influence their functionality, which is crucial for theory and electronics applications. First, channel dimensions, precisely length, and width, are pivotal. The size of these channels affects the transistor's ability to carry current and switching speeds; shorter channels typically enable...
423