MIM Capacitor Contact Plug Penetration for Leakage Control
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Solution Overview
Problem
As semiconductor devices integrate denser, the physical area of unit cells decreases, making it challenging to maintain capacitance in capacitors, especially with the use of high-k dielectric layers in metal-insulator-semiconductor capacitors, which often results in deteriorated leakage current characteristics.
Innovation Solution
The implementation of a metal-insulator-metal (MIM) capacitor structure with a specific configuration of electrodes and dielectric layers, including a first contact plug that penetrates and contacts both the top and side surfaces of a third electrode, increasing the contact area and reducing resistance, thereby enhancing capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of a dielectric layer is reduced to increase capacitance, then capacitance is improved, but leakage current characteristics deteriorate
Solution Approach 1:
The patent employs a composite dielectric structure consisting of a first dielectric layer and a second dielectric layer with different material properties. The first dielectric layer provides high capacitance, while the second dielectric layer suppresses leakage current, achieving both high capacitance and good leakage characteristics simultaneously through material composition optimization.
2Quantity of substance
If a high-k dielectric layer is used to increase capacitance, then capacitance is improved, but a low-k dielectric layer must be formed between the high-k dielectric layer and polysilicon layer, resulting in inability to obtain desired capacitance
Solution Approach 1:
The patent extracts the problematic low-k dielectric layer from the capacitor structure and replaces it with a contact plug that directly contacts the first electrode. This eliminates the capacitance-reducing interface while maintaining electrical connection, allowing the high-k dielectric layer to achieve its full capacitance potential without the need for additional low-k dielectric layers.
3Productivity
If the physical area of a unit cell decreases due to higher integration, then device density is improved, but the area occupied by the capacitor decreases, making it difficult to maintain capacitance
Solution Approach 1:
The patent transitions from a planar capacitor structure to a three-dimensional structure by forming the first electrode with penetrating portions that extend vertically through the dielectric layers. This vertical dimension expansion increases the effective electrode area without increasing the planar footprint, enabling high capacitance in a compact area suitable for high-density integration.
4Ease of manufacture
If a contact plug contacts only the top surface of an electrode, then fabrication is simplified, but contact area is limited and resistance is higher
Solution Approach 1:
The contact plug is formed to penetrate the third electrode and nest within the penetrating portions of the first and third electrodes, contacting both the top surface and side surfaces. This nested configuration maximizes the contact area between the contact plug and electrodes, reducing electrical resistance while maintaining a relatively simple fabrication process.
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 configuration increases capacitance by reducing resistance and improving electrical characteristics in semiconductor devices, addressing the challenge of maintaining capacitance in densely integrated semiconductor devices.
Implementation Method 1
a first contact plug penetrating the third electrode and contacting the first electrode. The first contact plug may contact a top surface of the third electrode and a side surface of the third electrode
Data Source
AI summary
A semiconductor device including a first electrode on a substrate, a second electrode on the first electrode, a first dielectric layer between the first electrode and the second electrode; a third electrode on the second electrode, a second dielectric layer between the second electrode and the third electrode, and a first contact plug penetrating the third electrode and contacting the first electrode, the first contact plug contacts a top surface of the third electrode and a side surface of the third electrode.