Semiconductor Interconnect Amorphous Substrate Parasitic Capacitance
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Solution Overview
Problem
Parasitic capacitance between semiconductor substrates and interconnects in high-frequency devices, such as switches, degrades signal quality due to the formation of inversion or accumulation layers, which is challenging to mitigate especially in patterned substrates with high process variance and incomplete charge compensation.
Innovation Solution
A method involving counter doping via shallow trench isolation and amorphization ion implantation to form amorphous or polycrystalline regions adjacent to the interconnects, preventing the formation of inversion or accumulation layers by ensuring Fermi level pinning and reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional interconnect structures are used over semiconductor substrates, then device integration is achieved, but parasitic capacitance forms between the interconnect and substrate degrading signal quality
Solution Approach 1:
An amorphous silicon layer is introduced as an intermediary between the crystalline semiconductor substrate and the interconnect. This amorphous layer acts as a mediator that prevents the formation of inversion or accumulation layers at the substrate surface, thereby eliminating the parasitic capacitance pathway while maintaining device functionality.
Solution Approach 2:
The crystalline structure of the semiconductor substrate is locally transformed into an amorphous phase in the region adjacent to the interconnect. This structural parameter change (from crystalline to amorphous) fundamentally alters the electrical properties of the substrate surface, preventing charge carrier accumulation and eliminating parasitic capacitance effects.
2Object-affected harmful factors
If doping is used to reduce parasitic capacitance, then charge compensation is attempted, but process variance increases and incomplete compensation occurs in patterned substrates
Solution Approach 1:
Instead of relying on precise doping parameter control, the invention changes the structural parameter of the substrate from crystalline to amorphous. This phase transformation provides a more robust and controllable method for eliminating parasitic capacitance, as the amorphous phase inherently prevents inversion layer formation without requiring precise dopant concentration control.
Solution Approach 2:
The invention converts the typically harmful amorphous phase (which is often considered a defect in semiconductors) into a beneficial feature. By deliberately creating an amorphous silicon layer at the substrate surface, the invention transforms what is normally a detrimental structural state into a mechanism that actively suppresses parasitic capacitance and improves signal quality.
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 effectively suppresses the formation of inversion or accumulation layers, thereby improving signal transmission quality and reducing process variance, leading to enhanced high-frequency device performance by minimizing parasitic capacitance.
Implementation Method 1
implanting dopant atoms into the at least one sidewall and the bottom of the opening
Implementation Method 2
implanting amorphization ions into the semiconductor substrate so as to at least partially amorphize a region adjacent to the at least one sidewall of the opening and a region adjacent to the bottom of the opening
Data Source
AI summary
A method for manufacturing a semiconductor device in accordance with various embodiments may include: forming an opening in a first region of a semiconductor substrate, the opening having at least one sidewall and a bottom; implanting dopant atoms into the at least one sidewall and the bottom of the opening; configuring at least a portion of a second region of the semiconductor substrate laterally adjacent to the first region as at least one of an amorphous or polycrystalline region; and forming an interconnect over at least one of the first and second regions of the semiconductor substrate.