Double-Side Biasing Nonvolatile Memory Cells
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Solution Overview
Problem
Fowler-Nordheim tunneling in nonvolatile memory cells requires large electric fields and voltage differences, making it inefficient for electron transport to the charge trapping structure.
Innovation Solution
A Double-Side-Bias (DSB) method is applied, where the source and drain regions are positively biased relative to the body region, and the gate region is positively biased relative to the source and drain regions, using lower voltage magnitudes to facilitate electron flow to the charge trapping structure, emulating Fowler-Nordheim operations while reducing voltage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Fowler-Nordheim tunneling is used to move electrons to the charge trapping structure, then electron transport is achieved, but large voltage differences and high power consumption are required
Solution Approach 1:
The patent changes the biasing parameters from conventional single-sided high voltage to double-sided biasing with lower voltages. Specifically, it applies positive bias to both source/drain regions relative to the body region, and positive bias to the gate region relative to source/drain regions, enabling efficient electron transport at reduced voltage magnitudes and power consumption
Solution Approach 2:
The patent segments the biasing approach into two independent bias arrangements: one for source/drain regions and another for the gate region. This segmentation allows each region to be optimized independently, achieving effective electron transport to the charge trapping structure while minimizing overall power consumption
2Ease of operation
If large voltage differences are applied for Fowler-Nordheim tunneling, then electron transport is enabled, but device complexity and design difficulty increase
Solution Approach 1:
The patent modifies the voltage parameters from large single-ended voltages to smaller differential voltages applied across multiple terminals. The double-sided biasing scheme uses lower magnitude voltages (e.g., source/drain biased by no more than 6V relative to body, gate biased by no more than 11V relative to source/drain), simplifying voltage application while maintaining effective electron transport
3Productivity
If conventional single-sided biasing is used, then structure simplicity is maintained, but programming and erasing efficiency is reduced
Solution Approach 1:
The patent divides the biasing structure into two independent bias arrangements: one controlling source/drain regions and another controlling the gate region. This segmentation enables simultaneous control of hole flow (from source/drain to body) and electron flow (from body to charge trapping structure), dramatically improving programming and erasing efficiency while adding manageable complexity
Solution Approach 2:
The double-sided biasing structure serves multiple functions simultaneously: it controls hole injection from source/drain to body, controls electron injection from body to charge trapping structure, and enables both programming and erasing operations through different bias configurations, making the system highly efficient and versatile
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 method allows for efficient electron addition to the charge trapping structure with lower voltage magnitudes, reducing power consumption and simplifying memory design, while also enabling hole addition through simultaneous two-sided band-to-band hot holes, improving programming and erasing efficiency.
Implementation Method 1
positively biasing the source and drain regions relative to the body region causes holes to flow from the source and drain regions to the body region
Implementation Method 2
positively biasing the gate region relative to the source and drain regions causes electrons to flow from the body region to the charge trapping structure
Implementation Method 3
Fowler-Nordheim tunneling is a known charge transport mechanism to move electrons from the source and drain of a nonvolatile memory cell to the charge trapping structure
Data Source
AI summary
Methods and apparatuses are disclosed for biasing the source-side and the drain-side of a nonvolatile memory to add electrons to the charge trapping structure.