Contact Liner Carbon Gradient for Dense Semiconductor Contacts
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Solution Overview
Problem
Existing semiconductor devices face challenges in scaling down while maintaining electrical stability and reducing capacitance between contacts, particularly in multi-gate transistors with three-dimensional channels.
Innovation Solution
The semiconductor device incorporates a contact liner with varying carbon concentrations at different heights along its sidewall, and a ratio of carbon to oxygen that changes with distance from the active pattern surface, enhancing the reliability and performance of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pitch size of the semiconductor device is decreased to increase device density, then device density is improved, but capacitance between contacts increases and electrical stability deteriorates
Solution Approach 1:
The contact liner is designed with non-uniform carbon concentration distribution, where the carbon concentration varies at different heights along the sidewall. This local quality variation allows different regions of the contact liner to serve different functions: regions with higher carbon concentration provide better capacitance reduction, while regions with lower carbon concentration maintain electrical stability, thereby resolving the contradiction between device density and electrical stability.
2Productivity
If the pitch size of the semiconductor device is decreased to increase device density, then device density is improved, but capacitance between contacts increases
Solution Approach 1:
The carbon concentration parameter in the contact liner is deliberately changed as a function of height along the sidewall. By controlling the carbon concentration to vary at different heights, the dielectric properties of the contact liner are optimized to reduce capacitance between closely-spaced contacts, enabling higher device density without suffering from increased parasitic capacitance.
3Ease of manufacture
If a uniform contact liner is used to simplify manufacturing, then manufacturing complexity is reduced, but electrical stability and capacitance control deteriorate
Solution Approach 1:
Instead of using a uniform contact liner, the invention employs a contact liner with spatially varying carbon concentration. This local quality differentiation enables precise control over electrical properties such as capacitance and electrical stability, demonstrating that the additional manufacturing complexity is justified by the significant improvement in device performance and reliability.
Data Source
AI summary
Semiconductor devices with improved performance and reliability and methods for forming the same are provided. The semiconductor devices include an active pattern extending in a first direction, gate structures spaced apart from each other in the first direction on the active pattern, a source/drain pattern on the active pattern, a source/drain contact on the source/drain pattern, and a contact liner extending along a sidewall of the source/drain contacts. A carbon concentration of the contact liner at a first point of the contact liner is different from a carbon concentration of the contact liner at a second point of the contact liner, and the first point is at a first height from an upper surface of the active pattern, the second point is at a second height from the upper surface of the active pattern, and the first height is smaller than the second height.