Dual Work-Function Gate Structure With Dielectric Diffusion Barrier
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Solution Overview
Problem
In semiconductor manufacturing, conductive materials from a first conductive layer diffuse into a second conductive layer during thermal processes, affecting the performance of the polycrystalline silicon layer in dual work-function gates, leading to issues like gate-induced drain leakage current.
Innovation Solution
A dielectric layer is introduced as a barrier between the first and second conductive layers to prevent diffusion, and the conductive layers are connected to form an equipotential, using a method that includes forming a substrate with trenches, depositing a first conductive layer, a dielectric layer, and a second conductive layer, with the dielectric layer blocking conductive material diffusion and enabling electron tunneling for equipotential connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual work-function gate structure with stacked conductive layers is used to solve gate-induced drain leakage current, then the device performance is improved, but conductive materials diffuse into each other during thermal processes
Solution Approach 1:
A dielectric layer is introduced as an intermediary barrier between the first conductive layer (metal) and the second conductive layer (polycrystalline silicon). This dielectric layer prevents direct contact and diffusion between the conductive materials during thermal processes, while still allowing the dual work-function gate structure to function effectively in suppressing gate-induced drain leakage current.
Solution Approach 2:
The gate structure is segmented into distinct functional layers: the first conductive layer for one work function, the dielectric barrier layer, and the second conductive layer for the other work function. This segmentation allows each layer to perform its specific function independently while maintaining overall system performance.
2Ease of manufacture
If thermal processes are applied during manufacturing, then the conductive layers are formed and connected, but conductive materials diffuse into each other
Solution Approach 1:
The dielectric layer serves as a thermal barrier that remains stable during manufacturing thermal processes. It allows the conductive layers to be formed and connected through standard thermal processes while preventing material diffusion, thus maintaining manufacturing precision despite the use of thermal processing.
Solution Approach 2:
The dielectric barrier layer is formed in advance between the conductive layers before thermal processes are applied. This preliminary action ensures that when subsequent thermal processing occurs, the conductive materials are already protected from diffusing into each other.
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 prevents conductive material diffusion, improves device performance by reducing gate-induced drain leakage current, and enhances the adhesive force between layers, ensuring reliable semiconductor operation.
Implementation Method 1
disposing between the first conductive layer and the second conductive layer the dielectric layer as a barrier layer so as to prevent the conductive materials in the first conductive layer from diffusing into the second conductive layer
Implementation Method 2
connecting the first conductive layer to the second conductive layer so as to form an equipotential
Data Source
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AI summary
Provided is a method for manufacturing a semiconductor structure. The method comprises: providing a substrate, wherein a trench is provided in the substrate; forming a first conductive layer in the trench, wherein the top of the first conductive layer is lower than the top of the trench; forming a dielectric layer on the first conductive layer; and forming a second conductive layer on the dielectric layer.