SOI Transistor Body-Tie Structure for Floating Body Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Partially-depleted Silicon-On-Insulator (SOI) transistors suffer from a floating body effect, leading to issues like kink effect, impact ionization, worse subthreshold swing, and lower drain to source breakdown voltage.
Innovation Solution
The semiconductor structure incorporates a butted body with a second type conductivity, located between the insulating layer and the active regions, to tie the body region to the active regions, thereby eliminating the floating body effect without increasing the device area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PD SOI transistors are used for simpler manufacturing, then manufacturing complexity is reduced, but floating body effects occur leading to kink effect, impact ionization, worse subthreshold swing, and lower breakdown voltage
Solution Approach 1:
The body region is segmented into a first doped region and a second doped region with different conductivity types. This segmentation allows the transistor to maintain PD SOI manufacturing simplicity while eliminating floating body effects through the opposing doped regions that tie down the body potential.
Solution Approach 2:
The invention changes the electrical parameters of the body region by introducing regions with different conductivity types (first and second conductivity types). This parameter change transforms the floating body characteristic into a controlled potential structure, improving subthreshold swing and breakdown voltage while maintaining manufacturing simplicity.
2Ease of manufacture
If the body thickness is increased to reduce depletion width issues, then manufacturing is simplified, but floating body effects worsen due to inadequate depletion
Solution Approach 1:
Instead of changing the physical dimension (body thickness), the invention changes the electrical parameter by introducing doped regions with different conductivity types. This parameter change effectively ties down the body potential without requiring thickness modification, thereby eliminating floating body effects while maintaining manufacturing simplicity.
Solution Approach 2:
The invention converts the harmful floating body effect into a beneficial controlled potential structure by introducing opposing doped regions. The floating body characteristic is transformed into a useful mechanism for potential control, improving device performance while maintaining the simplified PD SOI manufacturing approach.
3Area of stationary object
If conventional PD SOI structure is used, then device area is minimized, but subthreshold swing and breakdown voltage are degraded due to floating body
Solution Approach 1:
The invention applies local quality changes by introducing doped regions with different conductivity types in specific locations within the body region. These localized doped regions improve subthreshold swing and breakdown voltage without increasing the overall device area, as the changes are confined to specific zones rather than expanding the entire device footprint.
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.