Boron Nitride Channel Isolation for Scaled FET RC Delay
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Solution Overview
Problem
As field effect transistors (FETs) are scaled down, the width of the insulating material between adjacent sections of the channel structure is reduced, leading to increased resistance-capacitance (RC) delay due to the insulating material and conductive features on either side.
Innovation Solution
The implementation of a channel isolation structure formed with a low-k dielectric material, such as boron nitride, which reduces the dielectric constant and thereby minimizes RC delay. This structure is designed to cut channel structures into separate sections, providing proper isolation and reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the width of the insulating material between adjacent sections of the channel structure is reduced to accommodate scaled-down FETs, then the device density is improved, but the resistance-capacitance (RC) delay increases
Solution Approach 1:
The patent changes the dielectric constant parameter of the insulating material from conventional values (k≥3.0) to low-k values (k<3.0). This parameter change allows the insulating material to maintain effective electrical isolation while reducing parasitic capacitance, thereby decreasing RC delay even as the physical dimensions are scaled down to improve device density.
Solution Approach 2:
The patent employs composite material structures by combining low-k dielectric materials with specific conductive materials in the interconnect layers. This composite approach optimizes the overall RC delay by selecting materials with complementary properties - low-k materials for capacitance reduction and low-resistivity conductive materials for resistance reduction, achieving better performance than conventional single-material approaches.
2Ease of manufacture
If conventional insulating materials are used in scaled-down structures, then manufacturing simplicity is maintained, but RC delay increases due to higher parasitic capacitance
Solution Approach 1:
The patent modifies the dielectric constant parameter to low-k values while maintaining compatibility with existing manufacturing processes. The low-k dielectric materials are deposited using standard semiconductor fabrication techniques such as chemical vapor deposition (CVD) or atomic layer deposition (ALD), ensuring that manufacturing simplicity is preserved despite the material parameter change.
Solution Approach 2:
The patent utilizes porous low-k dielectric materials that incorporate voids or pores within the dielectric structure. These porous structures reduce the effective dielectric constant while the pore-filling processes and planarization steps integrate into existing manufacturing workflows, maintaining ease of manufacture while achieving reduced RC delay.
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 use of a low-k dielectric material in the channel isolation structure effectively limits RC delay by reducing parasitic capacitance, thereby improving the performance of scaled-down FETs.
Implementation Method 1
a low-k dielectric material in the channel isolation structure reduces a dielectric constant
Data Source
AI summary
A semiconductor device having a low-k isolation structure and a method for forming the same are provided. The semiconductor device includes channel structures, laterally extending on a substrate; gate structures, intersecting and covering the channel structures; and a channel isolation structure, laterally penetrating through at least one of the channel structures, and extending between separate sections of one of the gate structures along an extending direction of the one of the gate structures. A low-k dielectric material in the channel isolation structure comprises boron nitride.