Integrated Semiconductor Substrate Trenches for Parasitic Capacitance
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Solution Overview
Problem
Monolithic microwave integrated circuits require high-resistivity substrates to reduce eddy current and parasitic capacitance, but these substrates are expensive and prone to breakage, increasing production costs.
Innovation Solution
A monolithically integrated semiconductor device structure with trenches filled with low-k dielectric materials in the substrate, reducing the equivalent dielectric constant and increasing resistivity, thereby minimizing parasitic capacitance and eddy current while lowering production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high-resistivity substrate is used, then parasitic capacitance and eddy current are reduced, but production cost increases and substrate becomes more fragile
Solution Approach 1:
The substrate is segmented by introducing multiple trenches (first trenches and second trenches) that divide the continuous substrate into isolated regions. These trenches are filled with dielectric materials to create electrically isolated islands, thereby reducing parasitic capacitance and eddy current paths without requiring the entire substrate to be high-resistivity material.
Solution Approach 2:
Instead of using high-resistivity material throughout the entire substrate, the invention applies high-resistivity characteristics locally through dielectric-filled trenches at specific locations where parasitic effects need to be minimized. This allows standard low-cost substrates to achieve localized high-resistivity performance where needed.
2Reliability
If high-resistivity substrate is used, then substrate resistivity increases, but substrate becomes more prone to breakage
Solution Approach 1:
The substrate structure is segmented by introducing trenches that create physical and electrical isolation. These trenches are filled with dielectric materials that provide both electrical insulation (increasing effective resistivity) and mechanical support, thereby preventing substrate breakage while achieving the desired resistivity increase.
Solution Approach 2:
Dielectric materials are introduced as intermediary substances within the trenches. These dielectric materials serve as mediators that simultaneously provide electrical insulation to increase resistivity and mechanical reinforcement to prevent substrate breakage, resolving the contradiction between electrical performance and mechanical strength.
3Object-generated harmful factors
If high-resistivity substrate is used, then eddy current is reduced, but production cost increases greatly
Solution Approach 1:
The substrate is segmented by introducing trenches filled with dielectric materials that interrupt eddy current paths. This segmentation approach reduces eddy current losses without requiring expensive high-resistivity bulk material, thereby achieving the same electrical performance at lower production cost using standard substrates.
Solution Approach 2:
Instead of using expensive high-resistivity substrates, the invention employs cheap standard substrates combined with relatively inexpensive dielectric filling materials in trenches. This approach achieves the desired eddy current reduction at much lower material cost, making the solution economically viable for mass production.
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 solution effectively reduces parasitic capacitance and eddy current, improving device efficiency and performance while reducing production costs by using trenches filled with low-k dielectric materials in a silicon substrate, similar to high-resistivity substrates without the high cost and fragility issues.
Implementation Method 1
trenches filled with low-k dielectric materials in the substrate, reducing the equivalent dielectric constant and increasing resistivity
Implementation Method 2
require a high-resistivity silicon substrate or a high-resistivity SiC substrate to reduce possible eddy current, parasitic capacitance and/or current leakage in the substrate
Data Source
AI summary
A monolithically integrated semiconductor device structure includes: a substrate and a transistor; the substrate includes a transistor region; the transistor is positioned above the transistor region comprising at least one first trench and at least one second trench that are arranged in a horizontal direction and extend in a vertical direction; and the first trench is disposed below a drain of the transistor, and the second trench is disposed below a non-drain region of the transistor. In the present disclosure, the first trench and the second trench that are disposed in the substrate of the monolithically integrated semiconductor device structure, which may reduce the equivalent dielectric constant of the substrate and improve the equivalent resistivity, so that the parasitic capacitance and leakage current of the substrate below the transistor are reduced.