Semiconductor Source/Drain Buffer Layer for Stacking Fault Prevention
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Solution Overview
Problem
Semiconductor devices face challenges in achieving high integration, reliability, and multi-functionality due to limitations in electrical characteristics, particularly in the design of field effect transistors where stress and stacking faults affect channel resistance and performance.
Innovation Solution
The semiconductor device incorporates a source/drain pattern with a buffer layer and a main layer of silicon-germanium (SiGe) with varying germanium concentrations, where the buffer layer prevents stacking faults and the main layer ensures sufficient volume, and a gate dielectric pattern with ferroelectric materials to enhance capacitance and reduce operating voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional source/drain pattern is used in semiconductor devices, then the device structure is simple, but stacking faults occur and channel resistance increases
Solution Approach 1:
The source/drain pattern is segmented into multiple layers: a buffer layer (first layer) and a main layer (second layer). The buffer layer is positioned at the bottom to prevent stacking faults, while the main layer is positioned above to provide sufficient volume for electrical connection. This segmentation resolves the contradiction by introducing structural complexity that eliminates stacking faults and reduces channel resistance.
Solution Approach 2:
The source/drain pattern uses composite material structure with silicon-germanium (SiGe) in both the buffer layer and main layer. The SiGe material provides lattice mismatch control to prevent stacking faults while maintaining electrical conductivity. This composite approach improves reliability by preventing crystal defects while managing the complexity through material selection.
2Reliability
If germanium concentration in the main layer is increased to improve electrical conductivity, then channel resistance decreases, but manufacturing precision requirements increase
Solution Approach 1:
The source/drain pattern employs local quality variation through different germanium concentrations in different layers. The buffer layer contains SiGe with a first germanium concentration optimized for lattice matching and stacking fault prevention, while the main layer contains SiGe with a second germanium concentration optimized for electrical conductivity. This local differentiation allows each layer to be optimized for its specific function while managing manufacturing precision requirements.
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
This design improves the electrical characteristics of semiconductor devices by reducing channel resistance and increasing performance, specifically for PMOSFETs, while preventing stacking faults and enhancing sub-threshold swing characteristics.
Implementation Method 1
a buffer layer and a main layer, wherein the buffer layer prevents stacking faults and the main layer ensures sufficient volume
Implementation Method 2
a gate dielectric pattern with ferroelectric materials to enhance capacitance and reduce operating voltage
Data Source
AI summary
Disclosed is a semiconductor device including a first active pattern that extends in a first direction on an active region of a substrate, a first source/drain pattern in a recess on an upper portion of the first active pattern, a gate electrode that runs across a first channel pattern on the upper portion of the first active pattern and extends in a second direction intersecting the first direction, and an active contact electrically connected to the first source/drain pattern.