2T-1C DRAM Memory Cell Body Connection Lines for Floating Body Effect
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Solution Overview
Problem
Dynamic Random Access Memory (DRAM) cells with two transistors and one capacitor (2T-1C configuration) suffer from floating body effects, leading to degraded charge retention and power distribution issues due to unconnected body regions of the transistors.
Innovation Solution
The body regions of the transistors in the memory cells are coupled with reference voltages, eliminating the floating body effect by providing conductive pathways to ground or common plate voltage, thereby ensuring stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the body regions of transistors are left floating in 2T-1C memory cell configuration, then the structural simplicity is maintained, but charge retention degrades and power distribution issues occur
Solution Approach 1:
Body connection lines are introduced as intermediary conductive structures to connect the floating body regions of transistors to reference voltage nodes. These body connection lines serve as mediators that eliminate the harmful floating body effects while maintaining the overall simplicity of the 2T-1C memory cell architecture.
2Reliability
If body connection lines are added to couple body regions with reference voltages, then charge retention and power distribution improve, but device complexity increases
Solution Approach 1:
Multiple body connection lines are merged into shared conductive structures that serve multiple transistors. The body connection lines are combined with reference voltage distribution networks, allowing a single conductive structure to perform both body region connection and reference voltage distribution functions, thereby reducing overall complexity.
Solution Approach 2:
The body connection lines are designed to serve multiple functions: they connect body regions to reference voltages, provide power distribution, and establish stable electrical potentials. This multi-functionality reduces the need for separate dedicated structures for each function, offsetting the added complexity with functional consolidation.
Data Source
AI summary
Some embodiments include a memory cell with two transistors and one capacitor. The transistors are a first transistor and a second transistor. The capacitor has a first node coupled with a source/drain region of the first transistor, and has a second node coupled with a source/drain region of the second transistor. The memory cell has a first body region adjacent the source/drain region of the first transistor, and has a second body region adjacent the source/drain region of the second transistor. A first body connection line couples the first body region of the memory cell to a first reference voltage. A second body connection line couples the second body region of the memory cell to a second reference voltage. The first and second reference voltages may be the same as one another, or may be different from one another.