SOI Semiconductor Structure With Butted Body Against Floating Body Effect
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Solution Overview
Problem
Partially-depleted Silicon-On-Insulator (SOI) transistors suffer from the floating body effect, kink effect, impact ionization, and poor subthreshold swing due to their maximum depletion width being smaller than the body thickness, leading to lower drain-to-source breakdown voltage and other performance issues.
Innovation Solution
The introduction of a butted body with a second type conductivity, located between the insulating layer and the active regions, ties the body region to the active regions, eliminating the floating body effect without increasing the device area, by forming trenches and depositing the butted body and buffer layers using selective epitaxial growth methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a butted body is introduced to tie the body region to active regions, then the floating body effect is eliminated and subthreshold swing is improved, but the device structure becomes more complex
Solution Approach 1:
A butted body with opposite conductivity type is introduced as an intermediary element between the intrinsic body region and the active regions. This butted body acts as a mediator to tie the body region to the active regions, eliminating the floating body effect and improving subthreshold swing characteristics without requiring fundamental changes to the device architecture
Solution Approach 2:
The butted body is selectively formed only in specific regions where it is needed to connect the intrinsic body region to the active regions. This localized approach allows the solution to address the floating body effect in critical areas while maintaining simplicity in other parts of the device structure
2Manufacturing precision
If selective epitaxial growth is used to form butted body and buffer layers, then manufacturing precision is improved, but the manufacturing process becomes more complex
Solution Approach 1:
Selective epitaxial growth is employed to form the butted body and buffer layers by controlling growth parameters such as temperature, pressure, and gas flow rates. This method enables precise control over the thickness, composition, and location of the formed layers, ensuring high manufacturing precision while systematically managing process complexity through parameter optimization
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 enhances the semiconductor structure's performance by reducing the likelihood of the floating body effect, improving subthreshold swing, and increasing the drain-to-source breakdown voltage, thereby addressing the limitations of partially-depleted SOI transistors.
Implementation Method 1
The butted body has a second type conductivity different from the first type conductivity, and is located on the surface region of the substrate assembly so as to permit the body region to be tied to one of the active regions through the butted body
Implementation Method 2
by forming trenches and depositing the butted body and buffer layers using selective epitaxial growth methods
Data Source
AI summary
A semiconductor structure includes a substrate assembly and a semiconductor device. The semiconductor device is formed on the substrate assembly, and includes a body region, two active regions, and a butted body. The active regions are disposed at two opposite sides of the body region, and both have a first type conductivity. The body region and the active regions together occupy on a surface region of the substrate assembly. The butted body has a second type conductivity different from the first type conductivity, and is located on the surface region of the substrate assembly so as to permit the body region to be tied to one of the active regions through the butted body.