Composite Electrode Structure for DRAM Dielectric Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices shrink in size, the challenge of protecting underlying dielectric materials from damage during subsequent processing steps becomes increasingly difficult, leading to dielectric leakage and signal integrity issues in memory cells, such as DRAM cells, due to the proximity of components and shrinking design rules.
Innovation Solution
Incorporating a metal oxide material, like Aluminum Oxide (AlOx), within the electrode structure to act as a barrier, deposited between the conductive electrode portions, which increases the conduction band offset and energy barrier, reducing charge leakage without significantly impacting conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a thin conductive electrode is used to achieve high memory density, then device scaling is improved, but protection of underlying dielectric material from damage during subsequent processing steps deteriorates
Solution Approach 1:
The electrode is formed as a composite structure with a first conductive portion (e.g., titanium nitride) directly on the dielectric, a metal oxide barrier layer (e.g., aluminum oxide) in the middle, and a second conductive portion (e.g., platinum) on top. This composite structure provides both the conductivity needed for high-density memory operation and the protective barrier function to prevent dielectric damage during subsequent processing steps.
Solution Approach 2:
The metal oxide material serves as an intermediary barrier layer between the conductive electrode portions and the underlying dielectric material. This intermediate layer protects the dielectric from damage during subsequent processing while maintaining the electrical functionality of the electrode, effectively mediating between the conflicting requirements of conductivity and protection.
2Area of stationary object
If component proximity is increased to reduce device size, then area is reduced, but dielectric leakage increases
Solution Approach 1:
The composite electrode structure with metal oxide barrier layer provides enhanced protection against dielectric leakage even when components are in close proximity. The barrier layer creates an additional energy barrier that prevents charge leakage through the dielectric, enabling high-density integration without sacrificing reliability.
Solution Approach 2:
The metal oxide barrier layer changes the energy barrier parameters (conduction band offset, work function) at the electrode-dielectric interface. This parameter change increases the energy required for charge leakage, effectively suppressing dielectric leakage even when device dimensions are reduced and components are placed closer together.
3Reliability
If a barrier layer is added to protect the dielectric, then dielectric protection is improved, but electrode conductivity may be impacted
Solution Approach 1:
The composite electrode structure uses multiple conductive portions (first and second conductive materials) that flank the metal oxide barrier layer. These conductive portions maintain low resistance pathways for electrical current, ensuring that the overall electrode conductivity is preserved even with the presence of the insulating barrier layer in the middle of the electrode stack.
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 metal oxide layer effectively decreases voltage leakage by increasing the work function and band gap offset, enhancing the energy required for charges to traverse the dielectric, thereby reducing leakage and maintaining signal integrity in memory cells.
Implementation Method 1
increases the conduction band offset and energy barrier, reducing charge leakage
Implementation Method 2
increases the conduction band offset and energy barrier, reducing charge leakage
Implementation Method 3
The metal oxide layer effectively decreases voltage leakage by increasing the work function and band gap offset
Implementation Method 4
incorporating a metal oxide material, like Aluminum Oxide (AlOx), within the electrode structure to act as a barrier, deposited between the conductive electrode portions
Data Source
AI summary
Apparatuses, methods, and systems related to electrode formation are described. A first portion of a top electrode is formed over a dielectric material of a storage node. A metal oxide is formed over the first portion of the electrode. A second portion of the electrode is formed over the metal oxide.