Semiconductor Spacer Structure with Air Gap for Parasitic Capacitance Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices continue to shrink, existing manufacturing processes have not been entirely satisfactory in reducing parasitic capacitance, which affects performance.
Innovation Solution
The formation of a semiconductor structure with a gate structure, a bottom spacer at the lower part of the sidewall, and an upper spacer at the upper part of the sidewall, where the upper spacer includes an air gap to lower the dielectric constant, thereby reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device size is reduced to increase integration, then productivity and integration level are improved, but parasitic capacitance increases and performance deteriorates
Solution Approach 1:
The spacer structure is divided into multiple segments: a first spacer material layer and a second spacer material layer with different dielectric constants. This segmentation allows each layer to contribute differently to capacitance reduction, with the lower layer providing structural support and the upper layer providing lower parasitic capacitance, thereby resolving the contradiction between miniaturization and capacitance control.
Solution Approach 2:
Different regions of the spacer structure are assigned different material properties. The first spacer material layer (closer to the substrate) uses a material with higher dielectric constant for mechanical stability, while the second spacer material layer (closer to the gate) uses a material with lower dielectric constant to minimize parasitic capacitance. This local differentiation of material quality directly addresses the capacitance issue while maintaining device integrity.
2Productivity
If device size is reduced to increase integration, then productivity is improved, but manufacturing complexity increases
Solution Approach 1:
The method forms spacers in a sequential manner using preliminary actions: first forming the first spacer material layer, then forming the second spacer material layer on top of it. This step-by-step preliminary action approach allows each layer to be optimized independently while maintaining overall process control, reducing the complexity that would otherwise arise from attempting to form complex structures in a single step.
Solution Approach 2:
The spacer structure employs a nested configuration where the second spacer material layer is deposited on top of the first spacer material layer. This nesting approach allows both layers to coexist in a vertically stacked arrangement, enabling complex functionality (reduced parasitic capacitance with maintained structural integrity) without significantly increasing lateral footprint or process 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 approach improves the performance of semiconductor structures by reducing parasitic capacitance, enhancing the effectiveness of the semiconductor structure.
Implementation Method 1
the upper spacer includes an air gap to lower the dielectric constant, thereby reducing parasitic capacitance
Data Source
AI summary
A semiconductor structure and a method for forming the same are provided. The semiconductor structure includes a fin structure formed over a substrate and a gate structure formed across the fin structure. The semiconductor structure further includes a bottom spacer formed on a lower part of a sidewall of the gate structure and an upper spacer formed on an upper part of the sidewall of the gate structure. In addition, the upper spacer includes an air gap formed in a dielectric material.