3D MOS Capacitor Stack for Higher Capacitance in Less Area
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Solution Overview
Problem
Existing semiconductor technologies face challenges in improving device performance at reduced length scales, particularly in meeting the targets for advanced capacitive devices like MOS capacitors.
Innovation Solution
The development of a semiconductor structure with an MOS capacitor design that includes a stacked structure of M1I1M2I2M3, where M1 and M2 are conductive plates and I1 and I2 are insulator layers, along with embedded structures that increase the surface area of the conductive plates, enhancing capacitance without increasing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the minimum feature size is reduced to increase integration density, then more components can be integrated into a given area, but device performance deteriorates at reduced length scales
Solution Approach 1:
The patent transitions from planar capacitor structures to vertically stacked three-dimensional capacitor structures. By stacking multiple capacitor units (M1-I1-M2-I2-M3 layers) vertically, the design increases the effective capacitance area without expanding the lateral footprint, thereby maintaining high integration density while preserving device performance at reduced length scales.
Solution Approach 2:
The patent implements nested conductive plates and insulator layers where smaller capacitor structures are embedded within larger ones. The stacked configuration with embedded structures allows inner capacitor elements to be contained within the vertical stack, maximizing space utilization and maintaining performance despite miniaturization.
2Reliability
If the capacitance is increased to improve device performance, then the capacitor size must be increased, but the device area is limited
Solution Approach 1:
The patent resolves this contradiction by moving from two-dimensional planar capacitors to three-dimensional stacked capacitors. Multiple capacitor units are arranged vertically in the M1-I1-M2-I2-M3 stack configuration, enabling the capacitance to be increased by utilizing the vertical dimension rather than expanding the lateral area.
Solution Approach 2:
The patent divides the capacitor into multiple discrete stacked units (M1, I1, M2, I2, M3 layers) rather than using a single large planar capacitor. This segmentation allows the total capacitance to be distributed across multiple smaller vertical units, achieving high capacitance within a compact footprint.
Data Source
AI summary
A semiconductor structure includes a substrate and a capacitor over the substrate. The capacitor includes a silicide layer over the substrate. The capacitor includes a first dielectric layer over the silicide layer. The capacitor includes a metal gate structure over the first dielectric layer, where a top portion of the metal gate structure is over the substrate and a bottom portion of the metal gate structure extends into the substrate. The capacitor includes a second dielectric layer over the metal gate structure. The capacitor further includes a conductive structure over the second dielectric layer.