Memory Gate Work Function Layout for Signal Interference Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As process nodes miniaturize, memory signal interference becomes increasingly severe, necessitating optimization in memory manufacturing to reduce interference between active areas on both sides of an isolation structure.
Innovation Solution
A memory design featuring a substrate with an isolation structure and active areas, where a first gate structure with a higher work function conductive layer is formed at the bottom of a groove in the isolation structure, and a second gate structure with a lower work function material is formed in the active area, reducing electron transition and thus signal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If process nodes are miniaturized to increase integration density, then productivity and device capacity are improved, but signal interference between adjacent active areas becomes more severe
Solution Approach 1:
The patent applies different work function materials to different gate structures based on their location. Isolation structure gates use high work function materials (tungsten, titanium nitride, or tantalum nitride) to prevent electron accumulation, while active area gates use lower work function materials (titanium or tantalum) for proper switching operation. This local differentiation allows miniaturization while preventing signal interference between adjacent active areas.
Solution Approach 2:
The patent changes the work function parameter of gate materials to solve the signal interference problem. By selecting materials with different work functions for different gate structures, the patent modifies the electrical characteristics locally to prevent electron transition between active areas while maintaining proper transistor operation in active regions.
2Object-affected harmful factors
If a first conductive layer with high work function is added to the gate structure to reduce signal interference, then signal interference is reduced, but device complexity and manufacturing steps increase
Solution Approach 1:
The gate structure is segmented into multiple conductive layers with different work functions. The first conductive layer (high work function) is positioned at the bottom to prevent electron accumulation, while the second conductive layer (lower work function) is positioned above to enable proper switching. This segmentation allows the structure to perform multiple functions simultaneously.
Solution Approach 2:
The patent combines isolation structure gates and active area gates into a single continuous gate structure, with the first conductive layer extending across both regions. This merging simplifies manufacturing by allowing simultaneous formation of both gate types, while the second conductive layer is selectively formed only in active area grooves to provide the necessary work function variation.
3Object-affected harmful factors
If different work function materials are used for isolation and active area gates, then electron transition is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The first conductive layer is formed first to establish the isolation structure gates, and then the second conductive layer is selectively deposited only in the active area grooves. This preliminary action ensures that the high work function layer is already in place to prevent electron accumulation before the lower work function material is added, reducing the risk of contamination and improving manufacturing precision.
Solution Approach 2:
The first conductive layer acts as an intermediary between the substrate and the second conductive layer. It provides a stable, high work function base that prevents electron transition, while allowing the second conductive layer to be selectively formed in active areas. This intermediary structure simplifies the manufacturing process by decoupling the requirements for electron suppression and switching operation.
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 design effectively increases the threshold voltage of the first gate structure, reducing the number of actuated electrons and making it difficult to form a channel, thereby minimizing signal interference between adjacent active areas.
Implementation Method 1
the work function of the material of the first conductive layer is greater than that of the material of the second conductive layer
Data Source
AI summary
A memory and a method for manufacturing the same are provided. The memory includes: a substrate including an isolation structure and an active area between adjacent isolation structures; a first gate structure, the first gate structure locates in a first groove of the isolation structure, includes a first gate filled in the first groove, and the first gate includes a first conductive layer filled at the bottom of the first groove and a second conductive layer, the second conductive layer locates above the first conductive layer, and the work function of the material of the first conductive layer is greater than that of the material of the second conductive layer; a second gate structure, located in the second groove of the active area, includes a second gate filled in the second groove, and the material of the second gate is the same as that of the second conductive layer.