BEOL Transistor Barrier Layer Against Dielectric Impurity Invasion
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Solution Overview
Problem
In semiconductor devices, transistors formed in both FEOL and BEOL structures face challenges in maintaining sensitivity and reliability due to impurity invasion from barrier dielectric layers during operation, which affects their performance.
Innovation Solution
The implementation of a barrier layer structure in the BEOL structure that covers the entirety of the electrode element's lateral surfaces and separates the barrier dielectric layer into upper and lower portions, using materials like AlOx, HfOx, and SiNx, to prevent impurity invasion and enhance transistor sensitivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transistors are formed in BEOL structure with barrier dielectric layer, then device functionality is achieved, but impurity invasion occurs reducing transistor sensitivity and reliability
Solution Approach 1:
A barrier layer is introduced as an intermediary component between the electrode element and the barrier dielectric layer. This barrier layer specifically blocks impurities (oxygen and hydrogen ions) from the dielectric layer from invading the electrode element, thereby protecting transistor sensitivity and reliability while maintaining the necessary electrical functionality of the BEOL structure.
Solution Approach 2:
The original single-layer barrier dielectric structure is segmented into multiple portions by introducing a barrier layer at a specific position. This segmentation creates distinct functional zones: the barrier dielectric layer for electrical isolation and the barrier layer for impurity blocking, allowing each layer to optimize its specific function without interfering with the other.
2Reliability
If barrier layer is added to block impurities, then transistor sensitivity is maintained, but device structure complexity increases
Solution Approach 1:
The barrier layer is applied locally only where impurity invasion occurs - specifically at the interface between the electrode element and the barrier dielectric layer. This localized approach protects the critical transistor regions from impurities without requiring a complete restructuring of the entire BEOL device, thereby minimizing the increase in overall device complexity.
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 effectively blocks impurities such as oxygen and hydrogen ions, thereby maintaining or improving transistor sensitivity and reliability by isolating the electrode and active layers from the dielectric layer, ensuring stable operation.
Implementation Method 1
a barrier covering the entirety of a lateral surface of the electrode element... to prevent impurity invasion
Data Source
AI summary
A semiconductor device includes a FEOL structure and a BEOL structure. The BEOL structure is formed over the FEOL structure and includes a barrier dielectric layer, a transistor and a first barrier. The barrier dielectric layer has an upper surface and a lower surface. The transistor is partially formed in the barrier dielectric layer and includes an electrode element, and the electrode element has a first lateral surface, wherein the first lateral surface extends from the upper surface toward the lower surface. The first barrier covers the entirety of the first lateral surface of the electrode element.