Non-volatile Memory Electrode Work Function Engineering
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Solution Overview
Problem
Three-dimensional memory devices face performance deterioration due to variations in electric resistance between memory cells and source interconnects, affecting channel current and data readout accuracy.
Innovation Solution
A non-volatile memory device design featuring a conductive layer with a first electrode layer having a smaller work function than the second electrode layer, a channel body extending through the first electrode layer, and a charge storage portion between the electrodes, which reduces electric resistance and stabilizes channel current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If three-dimensional memory device structure is adopted to increase storage capacity, then storage capacity is improved, but variation of electric resistance between memory cells and source interconnect increases
Solution Approach 1:
The patent applies local quality by creating a specialized conductive layer with specific material composition and work function characteristics at the interface between the source interconnect and channel body. This local modification of electrical properties in the contact region reduces resistance variation without changing the overall three-dimensional memory structure, thereby maintaining high storage capacity while improving reliability.
Solution Approach 2:
The patent changes the work function parameter of the conductive layer by selecting materials with appropriate work function values (first electrode layer with work function of 4.0-4.5 eV, second electrode layer with work function of 4.5-5.0 eV). This parameter optimization reduces Schottky barrier height and contact resistance, thereby suppressing channel current variation while preserving the three-dimensional architecture for high storage capacity.
2Measurement precision
If electric resistance variation is suppressed to improve data readout accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the electrode structure into two distinct functional layers: a first electrode layer in contact with the channel body and a second electrode layer forming the source interconnect. This segmentation allows independent optimization of each layer's material properties to minimize resistance variation, improving data readout accuracy while keeping the overall structure manageable through clear functional separation.
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 solution effectively suppresses variations in channel current, improving the accuracy of data readout and overall performance of the memory device by reducing electric resistance and enhancing electron density in the inversion layer.
Implementation Method 1
At least a part of the second electrode on the conductive layer side has a work function smaller than a work function of the first electrode
Implementation Method 2
enhancing electron density in the inversion layer
Data Source
AI summary
A non-volatile memory device includes a conductive layer, a first electrode layer provided side by side with the conductive layer in a first direction, a second electrode layer provided between the conductive layer and the first electrode. At least a part of the second electrode on the conductive layer side has a work function smaller than a work function of the first electrode. The device further includes a first channel body extending through the first electrode layer in the first direction and a charge storage portion provided between the first electrode layer and the first channel body.