PDSOI MOSFET Body Coupling to Mitigate Floating Body Effect
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Solution Overview
Problem
Silicon on insulator (SOI) devices, particularly partially depleted SOI (PDSOI) MOSFETs, suffer from floating body effects (FBE) that cause leakage currents and operational inefficiencies due to the floating body potential affecting threshold voltage and channel current.
Innovation Solution
Coupling the body of the PDSOI transistor to one of its non-gate terminals, such as the local digit line, maintains a deterministic voltage and mitigates FBE by preventing arbitrary changes in body potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a thicker silicon layer is used in PDSOI devices to mitigate disturb and threshold voltage problems, then threshold voltage stability is improved, but floating body effect increases causing leakage current
Solution Approach 1:
The patent introduces a body connection terminal as an intermediary element that couples the body region to the source terminal. This mediator provides a controlled path for charge carriers, allowing the body potential to be stabilized without requiring a thinner silicon layer, thus maintaining threshold voltage stability while reducing leakage current through proper body potential control
Solution Approach 2:
The patent changes the electrical parameter of the body terminal by connecting it to the source terminal, thereby fixing the body potential at a known reference level. This parameter change transforms the floating body condition into a controlled body condition, reducing the harmful floating body effect while preserving the benefits of a thicker silicon layer
2Device complexity
If the body of PDSOI transistor is left floating to maintain simpler structure, then device complexity is reduced, but threshold voltage fluctuates and leakage current increases
Solution Approach 1:
The body connection terminal serves as a simple intermediary that adds minimal structural complexity while providing crucial electrical functionality. It connects the body region to the source terminal, establishing a reference potential that stabilizes threshold voltage without requiring complex control circuits or additional active elements
Solution Approach 2:
The body terminal, when connected to the source, automatically serves to stabilize the body potential and reduce floating body effects. The connection leverages the existing source potential to control the body region, allowing the device to self-regulate threshold voltage fluctuations without external intervention or complex control mechanisms
Data Source
AI summary
Devices and methods include a partially depleted silicon on insulator device that comprises a transistor. The transistor comprises a gate terminal. The transistor also includes a first non-gate terminal and a second non-gate terminal. Moreover, the first non-gate terminal is coupled to a body of the partially depleted silicon on insulator device.