Dual Sidewall Gate Spacers for High-Voltage Hot Carrier Reliability
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Solution Overview
Problem
The challenge in the semiconductor industry is to form reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, which affects the reliability and size of high-voltage devices.
Innovation Solution
A dual sidewall structure is formed in gate spacers within the high-voltage device region, increasing the thickness of the gate spacers, which improves the hot current injection reliability and allows high-voltage devices to operate effectively under high voltage with prolonged lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are decreased to increase functional density, then production efficiency is improved and costs are lowered, but fabrication process difficulty increases and device reliability deteriorates
Solution Approach 1:
The patent applies local quality by forming a dual sidewall structure specifically in the high-voltage device region while using a single sidewall structure in other regions. This localized structural enhancement improves hot carrier injection reliability in high-voltage devices without requiring all devices to be scaled down, thus maintaining device reliability while allowing continued scaling for standard devices.
Solution Approach 2:
The patent segments the chip into different regions with different gate spacer structures - high-voltage device regions receive enhanced dual sidewall structures while other regions use standard single sidewall structures. This segmentation allows targeted reliability improvement where needed while maintaining manufacturing efficiency for the overall chip production.
2Productivity
If feature sizes are decreased to increase functional density, then more devices can be integrated per chip area, but fabrication process complexity increases
Solution Approach 1:
The patent implements local quality by applying the complex dual sidewall formation process only to high-voltage device regions where it is critically needed, rather than applying it uniformly across the entire chip. This reduces overall fabrication complexity while maintaining high functional density through selective enhancement.
3Reliability
If gate spacer thickness is increased to improve hot carrier injection reliability, then device lifetime is prolonged, but device size increases
Solution Approach 1:
The patent applies local quality by increasing gate spacer thickness specifically in high-voltage device regions through dual sidewall formation, while maintaining thinner gate spacers in other regions. This localized thickening improves hot carrier injection reliability where high voltage operation occurs, without increasing the overall device size across the entire chip.
Solution Approach 2:
The patent segments the gate spacer structure into regions with different thicknesses - thicker dual sidewall gate spacers in high-voltage regions for improved reliability, and thinner single sidewall gate spacers elsewhere to minimize size increase and maintain scaling benefits.
Data Source
AI summary
A semiconductor device includes a substrate, a first gate structure and a second gate structure, a first gate spacer and a second gate spacer. The first gate spacer includes a first layer, a second layer over the first layer, a third layer over the second layer, a fourth layer over the third layer, and a fifth layer of the fourth layer, in which the first layer, the third layer, and the fifth layer of the first gate spacer are made of a same material. The second gate spacer includes a first layer, a second layer over the first layer, and a third layer over the second layer, in which the first layer and the third layer of the second gate spacer are made of a same material, and in which a lateral width of the first gate spacer is greater than a lateral width of the second gate spacer.