Memory cell with reduced parasitic capacitance and method of manufacturing the same
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Solution Overview
Problem
As semiconductor technology advances, managing electrical and mechanical properties of memory cells becomes challenging due to reduced dimensions, leading to increased parasitic capacitance and leakage current, which affects the performance and efficiency of memory devices like DRAM and SRAM.
Innovation Solution
The introduction of a low-k dielectric material, such as air or other suitable dielectric materials, is used to replace portions of the gate dielectric layer adjacent to the source/drain regions, reducing parasitic capacitance and lowering the electrical field, thereby improving access speed and reducing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dimensions of elements and distances between different elements are reduced to increase device density, then device density is improved, but parasitic capacitance increases
Solution Approach 1:
The patent applies local quality by replacing the gate dielectric layer with a low-k dielectric material specifically in regions adjacent to the source/drain regions, while maintaining the original gate dielectric in other areas. This localized substitution reduces parasitic capacitance at critical interfaces without compromising the overall gate control functionality, thereby resolving the contradiction between increased device density and reduced parasitic capacitance.
Solution Approach 2:
The patent changes the dielectric constant parameter by introducing low-k dielectric materials (with k-value lower than the original gate dielectric) into the gate structure. This parameter change directly reduces the parasitic capacitance formed between the gate and source/drain regions, allowing device density to increase while keeping parasitic effects under control.
2Productivity
If the dimensions of elements are reduced to improve device performance, then device performance is improved, but leakage current increases
Solution Approach 1:
The patent applies local quality by targeting specific regions adjacent to the source/drain regions for dielectric replacement, rather than uniformly modifying the entire gate structure. This localized approach reduces leakage current at the critical gate-source and gate-drain interfaces where parasitic effects are most pronounced, while maintaining proper gate control over the channel for high device performance.
Solution Approach 2:
The patent converts the potentially harmful high-k dielectric material into a beneficial low-k dielectric material in specific regions. By replacing the high-k material with low-k material adjacent to source/drain regions, the patent transforms what would otherwise be a source of leakage current into a beneficial structure that reduces parasitic capacitance and leakage while maintaining or enhancing device performance.
3Object-generated harmful factors
If low-k dielectric material is introduced to reduce parasitic capacitance, then parasitic capacitance is reduced, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the gate dielectric layer into distinct regions: the original gate dielectric material is retained in central regions while low-k dielectric material is introduced in adjacent regions near the source/drain structures. This segmented approach allows selective reduction of parasitic capacitance without requiring complete restructuring of the gate, thereby limiting the increase in device complexity.
Solution Approach 2:
The low-k dielectric material serves multiple functions: it acts as an insulator like the original gate dielectric while simultaneously providing reduced parasitic capacitance due to its lower dielectric constant. This multi-functionality allows the same material to fulfill both the electrical insulation requirement and the parasitic reduction goal, offsetting the added complexity with functional consolidation.
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 design enhances the performance of memory cells by lowering parasitic capacitance and leakage current, thus improving access speed without additional cost, while maintaining device functionality.
Implementation Method 1
managing electrical and mechanical properties of memory cells becomes challenging due to reduced dimensions, leading to increased parasitic capacitance
Implementation Method 2
The introduction of a low-k dielectric material, such as air or other suitable dielectric materials, is used to replace portions of the gate dielectric layer
Data Source
AI summary
The present application discloses a memory cell including a substrate, a word line, a first source/drain region, a second source/drain region, a first conductive via, and a second conductive via. The word line is arranged within the substrate. The first source/drain region and the second source/drain region are disposed in the substrate and on opposite sides of the word line. The first conductive via is disposed on the first source/drain region. The second conductive via is disposed on the second source/drain region. The second conductive includes a lower portion and an upper portion. The lower portion is extending into the second source/drain region. The upper portion is disposed over the lower portion.