MOS Gate Stack Magnetic Layer High-k Dielectric Leakage
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Solution Overview
Problem
High-k dielectric materials in MOS devices face a tradeoff between increased dielectric constant and higher gate leakage currents, as higher k values lead to reduced band-gaps, necessitating a balance between performance and leakage.
Innovation Solution
A magnetic layer is formed over a high-k dielectric layer in the MOS device, increasing the effective k value without reducing the bandgap, thereby minimizing gate leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-k dielectric materials with higher k values are used to improve MOS device performance and short channel control, then the dielectric constant increases, but the band-gap reduces resulting in increased gate leakage currents
Solution Approach 1:
The patent employs a composite gate dielectric structure consisting of multiple layers with different dielectric materials (e.g., HfO2, Al2O3, TiO2) and varying k-values. This composite approach allows the overall structure to achieve high effective k-value for improved short channel control while individual layers maintain sufficient band-gaps to limit gate leakage currents. The layered composite structure resolves the contradiction by distributing the functional requirements across multiple materials.
Solution Approach 2:
The patent applies local quality by assigning different dielectric materials with specific properties to different regions or layers within the gate dielectric stack. Each layer is strategically selected and positioned to optimize local electrical characteristics, creating a gradient or stepped structure where high-k materials are placed in regions requiring strong field control while lower-k but high-bandgap materials are positioned to minimize leakage pathways.
2Object-generated harmful factors
If high-k dielectric materials are used to reduce gate leakage currents, then the dielectric constant increases, but the band-gap reduction counteracts this benefit by increasing leakage
Solution Approach 1:
The composite gate dielectric structure combines materials with high k-values (for leakage reduction) with materials possessing wide band-gaps (for reliability). The synergistic interaction between these materials in the composite structure achieves both objectives: the high-k materials reduce leakage currents while the wide-bandgap materials maintain the necessary energy barrier, resolving the contradiction between leakage reduction and band-gap maintenance.
Solution Approach 2:
The patent introduces intermediary layers between high-k dielectric materials that serve as mediators. These intermediary layers have moderate k-values but high band-gaps, acting as buffer zones that prevent direct tunneling pathways while maintaining overall capacitive coupling. This intermediary approach allows the system to achieve leakage reduction benefits of high-k materials without suffering from their band-gap limitations.
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 effective k value of the high-k dielectric layer is significantly increased, enhancing MOS device performance without increasing gate leakage currents.
Implementation Method 1
A magnetic layer is formed over a high-k dielectric layer in the MOS device, increasing the effective k value without reducing the bandgap
Data Source
AI summary
An integrated circuit structure includes a semiconductor substrate, and a gate stack over the semiconductor substrate. The gate stack includes a high-k gate dielectric over the semiconductor substrate, and a magnetic compound over and in contact with the high-k gate dielectric. A source region and a drain region are on opposite sides of the gate stack. The gate stack, the source region, and the drain region are portions of a Metal-Oxide-Semiconductor (MOS) device.