V-Shaped Epitaxial Structures for Defect Control in Narrow Trenches
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Solution Overview
Problem
In semiconductor manufacturing, the increase in interconnect dimensions and aspect ratios leads to defects such as stacking faults and thread dislocations in FinFET devices, particularly in narrow trenches, which cause device leakage and low performance, as traditional epitaxial growth methods fail to effectively trap defects at the trench bottom.
Innovation Solution
Applying a passivating agent containing antimony to the silicon substrate within trenches, followed by exposure to a group IV-containing precursor, results in the formation of an epitaxial layer with a V-shaped structure having an exposed (111) plane at the trench bottom, which changes the growth rate and confines crystal defects, allowing for defect-free semiconductor layer growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional flat bottom epitaxial growth is used in narrow trenches, then the process is simple, but defects such as stacking faults and thread dislocations propagate to the top portion of semiconductor fins causing device leakage and low performance
Solution Approach 1:
The patent applies a passivating agent containing antimony to the silicon substrate portions exposed through trenches before epitaxial growth. This preliminary treatment modifies the substrate surface to control defect propagation during subsequent epitaxial growth, preventing stacking faults and thread dislocations from reaching the top portion of semiconductor fins.
Solution Approach 2:
The patent changes the crystal orientation parameter by exposing the silicon substrate to a group IV-containing precursor to form an epitaxial layer with a V-shaped structure having an exposed (111) plane at the bottom of trenches. This parameter change from traditional flat (100) bottom to V-shaped (111) bottom fundamentally alters defect propagation behavior, terminating defects at the trench bottom and preventing their propagation to upper portions.
2Productivity
If the trench aspect ratio is increased to achieve higher circuit density, then interconnect dimensions decrease, but defects are more likely to propagate and cause device leakage
Solution Approach 1:
The patent changes the geometric parameter of the trench bottom from flat to V-shaped with exposed (111) plane. This parameter change creates a physical barrier that terminates crystal defects at the trench bottom, effectively preventing defect propagation even in high aspect ratio trenches required for high circuit density applications.
Solution Approach 2:
The passivating agent containing antimony acts as an intermediary substance applied to the silicon substrate before epitaxial growth. This intermediary layer modifies the substrate surface properties to control and prevent defect propagation during the epitaxial growth process in narrow trenches.
3Reliability
If a V-shaped epitaxial structure with (111) plane is formed, then defects are trapped at the trench bottom, but the epitaxial growth process becomes more complex
Solution Approach 1:
The patent applies a passivating agent containing antimony as a preliminary treatment step before epitaxial growth. This preliminary action prepares the silicon substrate surface to enable subsequent formation of the V-shaped (111) plane structure, making the overall process more controllable and manufacturable.
Solution Approach 2:
The patent replaces traditional mechanical or physical methods of defect control with a chemical approach using a passivating agent containing antimony. This chemical substitution enables precise control of epitaxial growth and defect termination through chemical interactions at the substrate surface.
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 V-shaped epitaxial structure effectively terminates crystal defects at the trench bottom, preventing their propagation to the upper portion and ensuring defect-free growth of subsequent semiconductor layers, enhancing transistor performance and reliability.
Implementation Method 1
applying a passivating agent containing antimony to portions of a silicon substrate exposed through trenches
Implementation Method 2
exposing the silicon substrate to a group IV-containing precursor to form an epitaxial layer having a V-shaped structure having an exposed (111) plane at a bottom of the trenches
Data Source
AI summary
The present disclosure generally relate to methods of processing a substrate in an epitaxy chamber. The method includes applying a passivating agent containing antimony to portions of a silicon substrate exposed through trenches formed in a dielectric layer on the silicon substrate, while applying the passivating agent containing antimony, exposing the silicon substrate to a group IV-containing precursor to form an epitaxial layer having a V-shaped structure having an exposed (111) plane at a bottom of the trenches, and forming a semiconductor layer on the epitaxial layer.