Semiconductor Memory Dielectric Layer Thickness Segmentation
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Solution Overview
Problem
Non-volatile memory (NVM) devices face challenges in optimizing performance for both program and erase operations due to the trade-off between coupling ratio and effective electric field for charge retention, where a thicker dielectric layer improves coupling ratio but may hinder erase operations.
Innovation Solution
A dielectric layer with varying thicknesses is used, featuring a thicker portion to reduce capacitive coupling for enhanced program performance and a thinner portion to maintain effective erase operations, allowing for balanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a thicker dielectric layer is used, then coupling ratio is improved for lower operating voltage, but erase operation effectiveness deteriorates
Solution Approach 1:
The dielectric layer is segmented into two distinct portions with different thicknesses: a first dielectric portion with a greater thickness over the first active region to improve coupling ratio and reduce operating voltage, and a second dielectric portion with a lesser thickness over the second active region to maintain effective erase operations. This segmentation allows each portion to be optimized for its specific function.
Solution Approach 2:
Different regions of the dielectric layer are given different local qualities (thicknesses) to optimize performance. The first dielectric portion has a greater thickness locally over the first active region where high coupling ratio is needed, while the second dielectric portion has a lesser thickness locally over the second active region where effective erase operations are critical.
2Reliability
If a thinner dielectric layer is used, then erase operation effectiveness is improved, but coupling ratio deteriorates requiring higher operating voltage
Solution Approach 1:
The dielectric layer is divided into two portions with different thicknesses to simultaneously satisfy conflicting requirements. The second dielectric portion maintains a lesser thickness over the second active region to ensure effective erase operations, while the first dielectric portion compensates with greater thickness over the first active region to maintain adequate coupling ratio and lower operating voltage.
Solution Approach 2:
The dielectric layer exhibits different local qualities in different regions. Over the second active region, the dielectric has lesser thickness to maximize erase effectiveness, while over the first active region, it has greater thickness to maintain coupling ratio and reduce operating voltage requirements.
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 dielectric layer with different thicknesses optimizes both program and erase operations by increasing coupling ratio for lower operating voltage while ensuring effective charge retention and erasure.
Implementation Method 1
a thicker dielectric layer improves coupling ratio but may hinder erase operations
Data Source
AI summary
A memory device is provided. The memory device includes an active region in a substrate, an electrically-isolated electrode, and a dielectric layer. The electrically-isolated electrode is disposed over the active region. The dielectric layer is disposed between the electrically-isolated electrode and the active region and has a first dielectric portion having a first thickness and a second dielectric portion having a second thickness.