Three-Layer DRAM Capacitor Electrode for Leakage Control
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Solution Overview
Problem
As DRAM feature sizes decrease, the leakage effect of the capacitor structure becomes more pronounced, necessitating a solution to reduce associated side effects.
Innovation Solution
A semiconductor structure with a three-layer lower electrode configuration, where the second lower electrode layer has a higher work function than the first and third layers, is employed to ameliorate leakage and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the feature size of DRAM is reduced below a certain numerical value, then the integration density is improved, but the leakage effect of the capacitor structure becomes more pronounced
Solution Approach 1:
The lower electrode is divided into three distinct layers (first, second, and third lower electrode layers) with different work functions. This segmentation allows each layer to contribute differently to leakage prevention, with the high work function second layer serving as a barrier against electron emission while the other layers provide complementary functions.
Solution Approach 2:
Different regions of the lower electrode structure are assigned different work function values. The second lower electrode layer specifically has a higher work function than the first and third layers, creating a localized high-work-function region that effectively blocks leakage current at critical interfaces while maintaining overall electrode functionality.
2Object-generated harmful factors
If a multi-layer lower electrode structure is implemented to reduce leakage, then the leakage performance is improved, but the device complexity increases
Solution Approach 1:
The lower electrode is segmented into three functional layers with distinct work functions, where the second layer has a higher work function than the first and third layers. This segmentation enables targeted control of electron emission at different interfaces, reducing leakage current through the capacitor structure.
Solution Approach 2:
The work function parameter is varied across the three lower electrode layers, with the second layer specifically engineered to have a higher work function. This parameter change creates an energy barrier that suppresses electron emission and leakage current, addressing the leakage issue through material property optimization rather than structural complexity alone.
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 structure improves leakage performance and reduces overall resistance, enhancing the functionality and efficiency of the semiconductor device.
Implementation Method 1
a work function of the second lower electrode layer is greater than a work function of the first lower electrode layer and is greater than a work function of the third lower electrode layer
Data Source
AI summary
A semiconductor structure includes a substrate, a support structure located above the substrate and capacitor holes spaced apart, wherein the capacitor holes penetrate through the support structure, and lower electrodes located in the capacitor holes, wherein each lower electrode includes a first lower electrode layer, a second lower electrode layer, and a third lower electrode layer. The first lower electrode layer covers the bottom and the side walls of one of the capacitor holes, the second lower electrode layer is conformal to the first lower electrode layer and forms a cavity, and the third lower electrode layer is filled in the cavity, wherein the work function of the second lower electrode layer is greater than the work function of the first lower electrode layer and is greater than the work function of the third lower electrode layer.