Steep switching devices for low power applications: negative differential capacitance/resistance field effect...

Area of Science:

• Solid-state physics
• Semiconductor device engineering
• Materials science

Background:

• Conventional field-effect transistors (FETs) face limitations in achieving steep switching characteristics.
• Super steep switching, defined as a subthreshold slope below 60 mV/decade, is crucial for low-power electronics.
• Ferroelectric materials and threshold selectors offer pathways to overcome these limitations.

Purpose of the Study:

• To review the history and evolution of negative capacitance FETs (NCFETs) and phase FETs (also known as negative resistance FETs).
• To discuss the background, experimental investigations, and future perspectives of these steep switching devices.
• To provide a comprehensive overview of advancements in NCFET and phase FET technologies over the last decade.

Main Methods:

• Literature review of published studies on NCFETs and phase FETs over the past decade.
• Analysis of device structures, including ferroelectric integration in NCFETs and threshold selector integration in phase FETs.
• Discussion of experimental findings and theoretical underpinnings related to steep switching mechanisms.

Main Results:

• Both NCFETs and phase FETs demonstrate the ability to achieve sub-60-mV/decade subthreshold slopes.
• NCFETs utilize a ferroelectric oxide layer within the gate stack for enhanced switching.
• Phase FETs employ a threshold selector integrated with the transistor electrodes for negative resistance behavior.

Conclusions:

• NCFETs and phase FETs represent significant advancements in steep switching transistor technology.
• Continued research and development are essential for optimizing these devices for future low-power electronic applications.
• This review highlights the progress and outlines future directions for NCFET and phase FET research.