Semiconductor Structure With Low-K Isolation For Parasitic Capacitance Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor structures exhibit high parasitic capacitance due to large capacitance values, leading to increased RC delay effects and degraded performance as transistor dimensions are scaled down.
Innovation Solution
A semiconductor structure and fabrication method that involves forming an isolation structure with a dielectric constant less than the sidewall spacer, reducing parasitic capacitance by creating an isolation opening in the dielectric layer and inserting an isolation structure between the source-drain plug and the gate structure, thereby reducing the capacitance value of the source-drain capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor structure is formed with a sidewall spacer and dielectric layer, then the transistor can be fabricated with basic components, but the parasitic capacitance becomes large due to the capacitor formed by the source-drain plug, gate structure, and sidewall spacer
Solution Approach 1:
The patent extracts the harmful capacitive coupling effect by removing the traditional sidewall spacer that acts as a dielectric between the gate and source-drain regions. Instead of using a continuous dielectric layer with high capacitance, the invention introduces air gaps or voids to eliminate the parasitic capacitance pathway while maintaining the structural integrity and electrical isolation functions.
Solution Approach 2:
The patent employs air gaps and voids (effectively porous structures) in place of solid dielectric materials between the gate structure and source-drain regions. These air-filled spaces provide electrical isolation with minimal parasitic capacitance, as air has a dielectric constant close to 1, dramatically reducing the capacitive coupling compared to conventional dielectric materials.
2Productivity
If the capacitance value of the source-drain capacitor is increased to improve coupling, then the RC delay effect increases and transistor performance degrades
Solution Approach 1:
The patent fundamentally changes the dielectric parameter (capacitance) of the isolation structure by replacing solid dielectric materials with air gaps. This parameter change reduces the capacitance value in the RC time constant equation, thereby reducing the RC delay and improving transistor switching speed and overall performance.
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 approach effectively reduces parasitic capacitance and improves the performance of the semiconductor structure by minimizing the capacitance value of the source-drain capacitor, thereby mitigating RC delay effects.
Implementation Method 1
the parasitic capacitance of conventionally-formed semiconductor structures is large, and the performance of the semiconductor structure is poor and still needs to be improved
Implementation Method 2
forming an isolation structure in the isolation opening, wherein the isolation structure has a dielectric constant less than the sidewall spacer
Data Source
AI summary
A semiconductor structure and a method for fabricating the semiconductor structure are provided. The method includes forming a gate structure and a dielectric layer on a substrate; and forming a sidewall spacer on a sidewall surface of the gate structure. The method also includes forming a source and drain doped region in the substrate on both sides of the gate structure. The dielectric layer covers a surface of the sidewall spacer. In addition, the method includes forming a source-drain plug in the dielectric layer. The source-drain plug is connected to the source and drain doped region. Moreover, the method includes forming an isolation opening in the dielectric layer by at least partially removing the sidewall spacer. Further, the method includes forming an isolation structure in the isolation opening, wherein the isolation structure has a dielectric constant less than the sidewall spacer.