High-Voltage Gate Dielectric Structure Without Mask Removal Damage
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Solution Overview
Problem
High-voltage transistors face issues with breakdown voltage and surface defects due to the use of phosphoric acid in removing nitrogen-containing mask layers during gate dielectric formation, compromising device performance and lifetime.
Innovation Solution
Forming a semiconductor structure where the nitrogen-containing mask layer is converted into part of the gate dielectric layer, eliminating the need for its removal, thereby enhancing the thickness and durability of the gate dielectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If phosphoric acid is used to remove nitrogen-containing mask layer, then the mask layer is removed, but surface defects are generated and breakdown voltage is reduced
Solution Approach 1:
The patent converts the harmful nitrogen-containing mask layer into a beneficial component by transforming it into part of the gate dielectric layer through thermal processing. This eliminates the need for phosphoric acid removal while maintaining the electrical performance benefits of nitrogen in the dielectric, thereby resolving the contradiction between ease of manufacture and reliability
Solution Approach 2:
The patent introduces thermal processing as an intermediary mechanism to transform the nitrogen-containing mask layer into a functional part of the gate dielectric. This intermediary process eliminates the need for harmful chemical removal while achieving the desired structural transformation, thus improving breakdown voltage without compromising manufacturing ease
2Ease of manufacture
If phosphoric acid is used to remove nitrogen-containing mask layer, then the mask layer is removed, but device lifetime is reduced
Solution Approach 1:
The patent transforms the previously harmful nitrogen-containing mask layer into a beneficial component of the gate dielectric structure. By retaining and transforming rather than removing the mask layer, the device achieves improved reliability and extended lifetime while maintaining manufacturing simplicity
Solution Approach 2:
The patent changes the physical and chemical parameters of the nitrogen-containing mask layer through thermal processing, transforming it from a removable contaminant into a functional dielectric material. This parameter change eliminates the need for phosphoric acid removal and extends device lifetime by creating a more durable gate dielectric structure
3Reliability
If gate dielectric layer thickness is increased to improve breakdown voltage, then breakdown voltage is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the mask layer removal step with the gate dielectric formation process by transforming the mask layer into part of the dielectric structure. This consolidation eliminates separate removal steps and simplifies manufacturing while achieving the required gate dielectric thickness for high breakdown voltage
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 proposed method increases the breakdown voltage and reduces surface defects, leading to improved device performance and extended lifetime of high-voltage transistors.
Implementation Method 1
the nitrogen-containing mask layer is converted into part of the gate dielectric layer
Data Source
AI summary
A semiconductor structure includes: a semiconductor substrate; a gate dielectric layer over the semiconductor substrate; and a gate electrode over the gate dielectric layer. The gate dielectric layer includes a first portion and a second portion thinner than the first portion, wherein the gate electrode is over the first portion and the second portion, and the first portion includes a third portion including nitrogen and enclosed by the first portion.