DRAM Cell Trench Capacitor Floating Body Integration
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Solution Overview
Problem
Conventional one-transistor (1T) DRAM cells with a floating body region have diminished data-retention characteristics due to reduced charge storage capacity, which affects power dissipation and memory speed, and there is a need to improve charge storage capacity and reliability.
Innovation Solution
A semiconductor memory cell design that incorporates a trench capacitor directly coupled to an active body region of an access transistor, increasing charge storage capacity and data retention time by using the floating body effect for data storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional 1T DRAM cell with floating body region is used, then the cell size is reduced, but the charge storage capacity diminishes leading to poor data retention
Solution Approach 1:
The patent merges the trench capacitor structure with the floating body region by directly coupling the capacitor to the body, creating an integrated structure that combines charge storage and data retention functions within the same cell footprint, thereby improving data retention without increasing cell size
Solution Approach 2:
The floating body region serves multiple functions: it acts as both the data storage element (through charge accumulation) and the capacitor component (through direct coupling with the trench capacitor), eliminating the need for separate dedicated capacitor structures and improving overall cell efficiency
2Device complexity
If the floating body effect is used for data storage, then the cell complexity is reduced, but the charge storage capacity is insufficient affecting power dissipation and memory speed
Solution Approach 1:
The patent extends the charge storage capability into the vertical dimension by implementing a deep trench capacitor structure that couples with the floating body region, increasing the effective storage volume without expanding the lateral cell footprint, thus enhancing charge storage capacity while maintaining low complexity
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
The integration of a trench capacitor with the active body region enhances charge storage capacity, improving data retention time and reliability of the DRAM cell, while maintaining a smaller cell size.
Implementation Method 1
A semiconductor memory cell design that incorporates a trench capacitor directly coupled to an active body region of an access transistor, increasing charge storage capacity and data retention time by using the floating body effect for data storage
Data Source
AI summary
A semiconductor memory cell is provided that includes a trench capacitor and an access transistor. The access transistor comprises a source region, a drain region, a gate structure overlying the trench capacitor, and an active body region that couples the drain region to the source region. The active body region directly contacts the trench capacitor.