3D Semiconductor Memory Vertical Stack Structure
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Solution Overview
Problem
The integration of two-dimensional semiconductor devices is limited by the high cost and complexity of equipment needed for fine pattern formation, making it difficult to increase memory density, whereas three-dimensional semiconductor memory devices offer a solution but require innovative designs to enhance electrical characteristics and reliability.
Innovation Solution
A three-dimensional semiconductor memory device is designed with a stack structure featuring vertically arranged bit lines and semiconductor patterns, a gate electrode penetrating the stack, and a vertical insulating layer that supports data storage elements with specific electrode configurations to improve electrical connectivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If two-dimensional semiconductor devices use fine pattern formation to increase integration, then memory density improves, but manufacturing cost and equipment complexity increase significantly
Solution Approach 1:
The patent transitions from two-dimensional planar memory cells to three-dimensional vertically stacked memory cells. Multiple memory cell layers are stacked vertically, allowing memory density to increase without requiring finer lateral patterning. This vertical stacking approach achieves higher integration while avoiding the need for extremely expensive fine pattern formation equipment.
Solution Approach 2:
The memory device is divided into multiple discrete layers including first and second semiconductor layers, insulating layers, and conductive layers that are stacked vertically. Each layer can be formed using separate processing steps, allowing standard fabrication equipment to be used while achieving high density through the multi-layer structure.
2Quantity of substance
If two-dimensional semiconductor devices use fine pattern formation to increase integration, then memory density improves, but device complexity increases
Solution Approach 1:
The invention uses vertical stacking of multiple memory cell layers in the third dimension rather than increasing lateral density through finer patterns. This approach achieves higher memory density while maintaining relatively simple two-dimensional patterning processes, thereby reducing equipment complexity.
Solution Approach 2:
The vertically stacked structure allows the same fabrication processes to be applied repeatedly for each layer, making the manufacturing process more universal and less complex. Standard semiconductor processing equipment can be used for forming multiple layers through sequential deposition and patterning steps.
3Quantity of substance
If three-dimensional semiconductor memory devices are designed with vertically stacked structures, then memory density increases, but electrical characteristics and reliability may deteriorate
Solution Approach 1:
Insulating layers are introduced as intermediary elements between the first and second semiconductor layers. These insulating layers provide electrical isolation and proper potential distribution, ensuring reliable electrical characteristics while maintaining the vertical stacked structure for high memory density.
Solution Approach 2:
Different regions of the device are assigned different materials and functions: semiconductor layers for charge storage, insulating layers for isolation and dielectric function, and conductive layers for electrical connection. This local optimization of material properties ensures good electrical characteristics while achieving high density through vertical stacking.
Data Source
AI summary
Disclosed is a semiconductor memory device including a stack structure including layers which are vertically stacked on a substrate and each of which includes a bit line extending in a first direction and a semiconductor pattern extending in a second direction from the bit line, a gate electrode which is in a hole penetrating the stack structure and extending along a stack of semiconductor patterns, a vertical insulating layer covering the gate electrode and filling the hole, and a data storage element electrically connected to the semiconductor pattern. The data storage element includes a first electrode, which is in a first recess of the vertical insulating layer and has a cylindrical shape whose one end is opened, and a second electrode, which includes a first protrusion in a cylinder of the first electrode and a second protrusion in a second recess of the vertical insulating layer.