Epitaxial Word-Line Structure for DRAM Contact Area
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Solution Overview
Problem
The miniaturization of dynamic random access memory (DRAM) devices poses challenges in increasing the contact area between the capacitor contact and the active area, and reducing the resistance of the capacitor contact to enhance reliability and process window.
Innovation Solution
A word-line structure is developed with an epitaxial pattern embedded between the substrate and the word lines, increasing the contact area between the capacitor contacts and the active areas, and reducing the resistance by laterally extending epitaxial layers from the substrate into the word lines, while also recessing the barrier layer to avoid leakage current issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the critical dimension of DRAM is reduced to improve integration and operating speed, then the device size is miniaturized, but the contact area between capacitor contact and active area decreases and resistance increases
Solution Approach 1:
The patent introduces an epitaxial pattern that laterally extends from the substrate into the word line structure, adding a horizontal dimension to the contact area. This dimensional extension increases the contact area between capacitor contact and active area without increasing the vertical footprint, thereby improving reliability while maintaining miniaturization.
Solution Approach 2:
The epitaxial pattern is nested within the word line structure, specifically positioned between the insulating layer and the substrate. This nested configuration allows the contact area extension to be integrated within the existing device architecture without requiring additional external space, resolving the contradiction between miniaturization and contact area.
2Productivity
If the critical dimension is reduced to meet miniaturization demands, then electronic products achieve lightness and smallness, but the process window and manufacturing precision become more challenging
Solution Approach 1:
The patent changes the physical and chemical parameters of the contact region by introducing an epitaxial pattern with specific material composition and structural characteristics. This parameter change creates a more favorable electrical contact region that is more tolerant to manufacturing variations, thereby improving the process window while maintaining miniaturization.
Solution Approach 2:
The epitaxial pattern acts as an intermediary structure between the substrate and the word line, providing a transition region that facilitates better electrical contact. This intermediary structure helps to bridge the gap caused by miniaturization, making the manufacturing process more robust and less sensitive to dimensional variations.
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 solution enhances the reliability and process window of the memory device by increasing the contact area and reducing resistance, thereby improving the reading speed and efficiency.
Implementation Method 1
performing an epitaxial growth process to form a plurality of epitaxial layers on the upper sidewalls of the substrate
Data Source
AI summary
Provided is a word-line structure including a substrate, a word line, and an epitaxial pattern. The word line is embedded in the substrate. The word line includes a conductive layer, a barrier layer, an insulating layer, and a gate dielectric layer. The barrier wraps a lower portion of the conductive layer. The insulating layer wraps an upper portion of the conductive layer. The gate dielectric layer surrounds the insulating layer and the barrier layer to electrically isolate the barrier layer from the substrate. The epitaxial pattern is disposed between the insulating layer and the substrate and in contact with the substrate. A memory device including the word-line structure and a method of manufacturing the same are also provided.