Hemi-Cylindrical Nanowire Back-Gate Transistor for Leakage Control
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Solution Overview
Problem
Current methods for controlling the threshold voltage of transistors are inefficient, leading to challenges in managing off-state leakage currents such as gate-induced drain leakage (GIDL).
Innovation Solution
A semiconductor device with a back-bias region and a buried insulating layer is designed, where the back-bias region is offset-aligned with the drain, and the body is configured as a hemi-cylindrical nanowire with a gate electrode covering its top and lateral surfaces, reducing overlap and enhancing electric field transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to control threshold voltage, then device complexity is reduced, but threshold voltage control precision deteriorates
Solution Approach 1:
The device is segmented into distinct functional regions: a back-bias region formed in the substrate, a buried insulating layer separating the back-bias region from the body, and a gate electrode structure. This segmentation allows independent control of threshold voltage through the back-bias region while maintaining simple overall device architecture.
Solution Approach 2:
A buried insulating layer is introduced as an intermediary element between the back-bias region and the body. This intermediate layer enables electric field transmission from the back-bias region to modulate threshold voltage, while also providing electrical isolation and preventing direct contact that would complicate the device structure.
2Measurement precision
If back-bias region is positioned to maximize overlap with body, then threshold voltage control is enhanced, but off-state leakage current increases
Solution Approach 1:
The back-bias region is positioned with partial overlap with the body rather than full overlap, creating different electrical conditions in different regions. The offset alignment ensures that the back-bias region provides threshold voltage control where needed while avoiding direct alignment with the drain that would cause GIDL, thus achieving local optimization of electrical properties.
Solution Approach 2:
The back-bias region is offset-aligned relative to the drain to prevent the formation of high electric fields at the drain junction that would cause gate-induced drain leakage. This preliminary structural arrangement counteracts the potential harmful effect before it can occur during device operation.
3Use of energy by moving object
If body is configured as hemi-cylindrical nanowire with gate covering top and lateral surfaces, then electric field transmission efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The body is formed as a hemi-cylindrical nanowire with curved lateral surfaces instead of flat geometry. This curved structure provides uniform electric field distribution when the gate electrode covers the top and lateral surfaces, improving electric field transmission efficiency. The hemi-cylindrical shape can be achieved through standard semiconductor fabrication techniques such as selective epitaxial growth or nanowire formation methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for precise control of the threshold voltage and significantly reduces off-state leakage currents, improving the electrical properties of the semiconductor device.
Implementation Method 1
a gate electrode covering top and lateral surfaces of the body
Implementation Method 2
A buried insulating layer covers the substrate and the back-bias region
Data Source
AI summary
A back-bias region is disposed on a substrate. A buried insulating layer covers the substrate and the back-bias region. A body is formed on the buried insulating layer and partially overlaps the back-bias region. A drain is in contact with the body. A gate electrode covers top and lateral surfaces of the body.