Symmetrical MIM Capacitor Insulator Structure for Breakdown Voltage Balance
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Solution Overview
Problem
Metal-insulator-metal (MIM) capacitors with asymmetric capacitor insulator structures exhibit significant differences in forward and reverse biased breakdown voltages, limiting their utility, especially in bipolar applications due to the large disparity between these voltages.
Innovation Solution
A symmetrical capacitor insulator structure is implemented, comprising at least three dielectric structures vertically stacked, where the bottom half is a mirror image of the top half in terms of dielectric materials, reducing the difference between forward and reverse biased breakdown voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an asymmetric capacitor insulator structure is used, then the manufacturing process is simpler, but the difference between forward and reverse biased breakdown voltages is large, limiting utility in bipolar applications
Solution Approach 1:
The patent applies asymmetry in reverse - it deliberately creates a symmetrical structure where the capacitor insulator structure is configured such that a bottom half thereof is a mirror image of a top half thereof. This symmetry ensures that forward and reverse biased breakdown voltages are comparable, resolving the reliability issue while maintaining manufacturing feasibility through standardized deposition processes
Solution Approach 2:
The capacitor insulator structure is segmented into multiple dielectric layers (first dielectric layer, second dielectric layer, third dielectric layer) with specific arrangements. The first and third dielectric layers are positioned symmetrically relative to the top and bottom electrodes, while the second dielectric layer is positioned in the middle, creating the mirror image configuration that achieves voltage symmetry
2Reliability
If a symmetrical capacitor insulator structure is implemented, then the difference between forward and reverse biased breakdown voltages is minimized, but the device complexity increases
Solution Approach 1:
The patent applies local quality by assigning different dielectric materials to different regions of the capacitor insulator structure. The first, second, and third dielectric layers are formed from different dielectric materials with different dielectric constants, allowing each layer to contribute differently to the overall capacitance while maintaining the symmetrical configuration. This enables performance optimization without requiring complete structural symmetry
Data Source
AI summary
Various embodiments of the present application are directed towards an integrated chip structure. The integrated chip structure includes a bottom electrode over a substrate, a top electrode over the bottom electrode, and a capacitor insulator structure between the bottom electrode and the top electrode. The capacitor insulator structure includes a first dielectric layer, a second dielectric layer over the first dielectric layer, and a third dielectric layer over the second dielectric layer. The first dielectric layer includes a first dielectric material. The second dielectric layer includes a second dielectric material that is different than the first dielectric material. The second dielectric material is an amorphous solid. The third dielectric layer includes the first dielectric material.