Porous Dielectric Spacers Reduce Coupling Capacitance
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Solution Overview
Problem
As semiconductor devices are scaled down, challenges arise in achieving improved quality, yield, performance, and reliability while reducing complexity, particularly in minimizing capacitive coupling between conductive features, which affects RC delay and current consumption.
Innovation Solution
A semiconductor device design incorporating porous spacers and a capping layer with porosity between 25% and 100% between source/drain regions and the gate structure, along with an insulating layer, to reduce coupling capacitance and operating current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional dense dielectric structures are used between conductive features, then structural stability is maintained, but capacitive coupling increases leading to higher RC delay and current consumption
Solution Approach 1:
The patent applies porous dielectric materials (such as porous silicon oxide or porous silicon nitride) between conductive features instead of conventional dense dielectrics. The porous structure reduces the dielectric constant of the material, thereby decreasing capacitive coupling between adjacent conductors. This directly addresses the energy loss issue by reducing leakage current and RC delay, while the porous structure itself becomes the distinguishing feature of the dielectric layer.
Solution Approach 2:
The patent changes the physical and electrical parameters of the dielectric material by introducing porosity. Specifically, it modifies the dielectric constant (k-value) of the material from typical dense values (e.g., k=3.9 for standard silicon oxide) to lower porous values (e.g., k=2.0-3.0), thereby reducing capacitive effects. This parameter change enables lower operating current and reduced RC delay without fundamentally altering the device architecture.
2Productivity
If device dimensions are scaled down to improve computing ability, then productivity increases, but capacitive coupling effects become more significant increasing RC delay
Solution Approach 1:
As device dimensions scale down, the patent employs porous dielectric materials to maintain adequate spacing between conductors while reducing their capacitive interaction. The lower dielectric constant of porous materials compensates for the reduced physical spacing, thereby controlling RC delay even as feature sizes decrease and device density increases.
Solution Approach 2:
The patent introduces a new dimensional aspect by creating porous structures within the dielectric layer, effectively adding porosity as a controlling dimension. This allows optimization of electrical properties (reducing capacitive coupling) independent of the lateral and vertical dimensions of the conductors themselves, providing an additional degree of freedom for scaling.
3Loss of energy
If porosity of spacers and capping layer is increased to reduce coupling capacitance, then RC delay decreases, but mechanical strength may be compromised
Solution Approach 1:
The patent utilizes porous materials with controlled porosity levels (typically 30-70%) that balance electrical and mechanical requirements. The porous structure reduces dielectric constant for lower RC delay, while the remaining solid matrix maintains sufficient mechanical strength. The porosity is carefully controlled to achieve the optimal trade-off between electrical performance and structural integrity.
Solution Approach 2:
The patent employs composite porous dielectric structures that combine multiple materials or phases to achieve both low dielectric constant and adequate mechanical strength. The composite nature allows optimization of both electrical and mechanical properties simultaneously, as the different components contribute differently to each property.
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 reduces coupling capacitance, thereby minimizing RC delay and lowering operating current consumption, enhancing the performance and reliability of semiconductor devices.
Implementation Method 1
two porous spacers positioned between the source/drain regions and the gate structure, wherein a porosity of the two porous spacers is between about 25% and about 100%; a porous capping layer positioned on the gate structure and between the two porous spacers, wherein a porosity of the porous capping layer is between about 25% and about 100%
Data Source
AI summary
The present disclosure provides a semiconductor device with a porous dielectric structure for reducing capacitive coupling between conductive features. The semiconductor device includes a substrate; a gate structure positioned above the substrate; two source/drain regions positioned adjacent to two sides of the gate structure; two porous spacers positioned between the source/drain regions and the gate structure, wherein a porosity of the two porous spacers is between about 25% and about 100%; a porous capping layer positioned on the gate structure and between the two porous spacers, wherein a porosity of the porous capping layer is between about 25% and about 100%; and an insulating layer disposed over the two porous spacers and the porous capping layer.