Semiconductor devices
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Solution Overview
Problem
Current semiconductor devices face challenges in scaling density and effectively suppressing short channel effects while maintaining current control and reliability, particularly in multi-gate transistors with three-dimensional channels.
Innovation Solution
The semiconductor device incorporates a multi-channel active pattern with a lower pattern and sheet patterns, featuring gate structures with a semiconductor liner film and filling film made of silicon-germanium, where the germanium fraction varies between layers, and includes inner gate structures and a source/drain pattern with specific geometric configurations to enhance performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-gate transistors with three-dimensional channels are used to increase device density, then scaling is improved and current control capability is enhanced, but short channel effects become more pronounced and manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating non-uniform germanium concentration distributions within the channel region. The germanium fraction varies spatially, with higher concentrations near the channel to suppress short channel effects, and lower concentrations in other regions to maintain carrier mobility. This localized material property variation resolves the contradiction by addressing SCE suppression specifically where needed without compromising overall device performance.
Solution Approach 2:
The patent employs composite materials by combining silicon and germanium in varying proportions to form silicon-germanium alloy channels. The multi-layer structure with different germanium fractions (e.g., SiGe1, SiGe2, SiGe3 with Ge fractions of 0.2, 0.4, 0.6 respectively) creates a composite material system that simultaneously achieves high density scaling and effective SCE suppression through tailored material properties.
2Reliability
If multi-gate transistors with three-dimensional channels are used to improve current control capability, then device performance is enhanced, but manufacturing complexity and process difficulty increase
Solution Approach 1:
The patent applies segmentation by dividing the channel into multiple distinct layers with different germanium fractions. Instead of using a single complex three-dimensional gate structure, the channel is segmented into SiGe1, SiGe2, and SiGe3 layers, each with optimized germanium content. This segmentation simplifies the manufacturing process by allowing independent optimization of each layer while maintaining effective current control through the multi-layer configuration.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the germanium fraction parameter across different channel layers. The germanium fraction serves as a controllable parameter that is adjusted to optimize both current control capability and manufacturing feasibility. By changing this material composition parameter rather than complicating the structural geometry, the patent achieves enhanced current control with manageable manufacturing complexity.
3Reliability
If germanium fraction is increased to suppress short channel effects, then device reliability improves, but carrier mobility and current drive capability may deteriorate
Solution Approach 1:
The patent applies local quality by creating a non-uniform germanium concentration profile where high germanium fractions (0.4-0.6) are positioned specifically in regions that benefit from SCE suppression, while lower germanium fractions (0.2-0.4) are maintained in regions where carrier mobility is critical. This localized optimization resolves the contradiction by providing enhanced reliability where needed without sacrificing overall current drive capability.
Solution Approach 2:
The patent employs composite materials by creating a multi-layer silicon-germanium structure with graded germanium compositions. The composite channel consists of SiGe1, SiGe2, and SiGe3 layers with progressively varying germanium fractions, forming a material system that combines the SCE-suppressing properties of high-germanium regions with the high-mobility characteristics of low-germanium regions, thereby achieving both improved reliability and maintained current drive capability.
Data Source
AI summary
A semiconductor device having improved performance and reliability. The semiconductor device may include a lower pattern extending in a first direction, and a plurality of sheet patterns spaced apart from the lower pattern in a second direction perpendicular to the first direction. A plurality of gate structures may be on the lower pattern and spaced apart in the first direction, and a source/drain pattern, which may include a semiconductor liner film and a semiconductor filling film on the semiconductor liner film. A liner recess that is defined by an inner surface of the semiconductor liner film may include a plurality of width extension regions, and a width of each width extension region in the first direction may increase and then decreases, as a distance increases in the second direction from an upper surface of the lower pattern.