Multi-Dielectric Capacitor Structure for Edge Leakage and Breakdown
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Solution Overview
Problem
As semiconductor devices strive for increased memory density and performance, the thinning of dielectric materials in high-stress circuits leads to reliability issues due to dielectric breakdown, particularly in charge pump circuits of NAND memory devices, where capacitors operate at high voltage levels.
Innovation Solution
The implementation of capacitor structures with optimized dielectric material regions of varying thicknesses, including a low-voltage dielectric material overlying peripheral regions and a super low-voltage dielectric material overlying central regions, tailored to withstand higher voltages with reduced leakage and improved resistance, while maintaining minimal capacitance reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of dielectric material is reduced to increase device density, then memory density is improved, but dielectric breakdown reliability deteriorates
Solution Approach 1:
The patent applies local quality by using different dielectric materials with different breakdown voltages in different regions of the capacitor structure. Specifically, a first dielectric material with higher breakdown voltage is used in regions subjected to higher electric fields (such as near the semiconductor substrate), while a second dielectric material with lower breakdown voltage is used in regions with lower electric field stress. This spatial differentiation of material properties allows the structure to withstand high voltages locally where needed while maintaining overall compact dimensions for high density.
Solution Approach 2:
The patent employs composite materials by combining multiple dielectric materials in a single capacitor structure. The composite structure consists of at least two different dielectric materials stacked or arranged in specific configurations, where each material contributes its unique electrical properties. This composite approach enables the capacitor to achieve both high breakdown voltage resistance (through the high-voltage-rated dielectric material) and compact size (through the low-voltage-rated but thin dielectric material), thereby resolving the contradiction between density and reliability.
2Quantity of substance
If capacitor size is reduced to increase integration, then device density is improved, but voltage handling capability deteriorates
Solution Approach 1:
The patent applies local quality by strategically placing high-breakdown-voltage dielectric material in specific regions of the capacitor where electric field concentration occurs, such as near the semiconductor substrate interface and at edges. This localized use of high-voltage material provides enhanced voltage withstand capability precisely where needed, while the rest of the capacitor can use thinner low-voltage material to reduce overall size and increase integration density.
Solution Approach 2:
The patent uses composite materials to create a capacitor structure that combines high-voltage and low-voltage dielectric materials in a multi-layer configuration. The high-voltage dielectric layer provides the necessary voltage handling capability in a thin profile, while the low-voltage dielectric layer contributes to high capacitance in a compact form. This composite structure enables small-sized capacitors to withstand high voltages, thereby increasing integration density without sacrificing voltage handling capability.
3Volume of moving object
If dielectric material thickness is reduced to maintain capacitance in smaller devices, then device size is reduced, but leakage current increases
Solution Approach 1:
The patent applies local quality by using different dielectric materials with different electrical properties in different regions of the capacitor. Specifically, materials are selected and positioned to optimize the balance between capacitance, size, and leakage characteristics. High-k dielectric materials may be used in regions where high capacitance is needed, while low-leakage materials are used in regions where leakage prevention is critical, such as near the semiconductor substrate interface.
Solution Approach 2:
The patent employs composite materials to create a multi-layer dielectric structure where each layer is optimized for specific functions. One layer may be designed for high capacitance (using high-k material), another for low leakage (using low-defect-density material), and another for mechanical stability. This composite structure enables the capacitor to achieve high capacitance in a reduced volume while maintaining low leakage current through the synergistic combination of different material properties.
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 enhances the reliability of semiconductor devices by reducing leakage along the edges of capacitor structures and enabling operation at increased voltages without dielectric breakdown, while maintaining capacitance, through the strategic use of differing dielectric material thicknesses and self-aligned gate edges.
Implementation Method 1
a first dielectric material overlying at least a portion of the peripheral region of the active area and a second dielectric material adjacent the first dielectric material and overlying the central portion of the active area
Data Source
AI summary
A semiconductor structure includes a capacitor structure comprising an active region comprising opposing field edges parallel to a first horizontal direction and a gate region comprising opposing gate edges parallel to a second horizontal direction transverse to the first horizontal direction. The semiconductor structure also comprises a first dielectric material adjacent at least one of the opposing field edges or the opposing gate edges and a second dielectric material adjacent the active area and abutting portions of the first dielectric material. A height of the second dielectric material in a vertical direction may be less than the height of the first dielectric material. Semiconductor devices and related methods are also disclosed.