Nanowire Transistor Underlayer Etch Stop for Source Drain Protection
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Solution Overview
Problem
The challenge in nanowire transistor fabrication lies in preventing damage to source and drain structures during the removal of sacrificial layers, as existing etch processes can lead to shorting between transistor components due to low selectivity of materials used in these structures.
Innovation Solution
Incorporating an underlayer etch stop structure that is selective to the sacrificial materials, allowing for their removal without damaging the source and drain structures, thereby protecting them from etching damage during the nanowire release process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etch processes are used to remove sacrificial layers during nanowire fabrication, then the sacrificial layers can be removed, but the source and drain structures are damaged due to low material selectivity
Solution Approach 1:
An underlayer etch stop structure is introduced as an intermediary layer between the source/drain structures and the sacrificial layers. This underlayer has high selectivity to the sacrificial material, allowing the etch process to remove sacrificial layers while stopping before damaging the source and drain structures.
Solution Approach 2:
The underlayer etch stop structure is formed preliminarily before the sacrificial layers are deposited. This preliminary structure is specifically designed to protect the source and drain regions during subsequent etching operations, preventing damage before it can occur.
2Reliability
If the etch process is made more selective to sacrificial materials, then source and drain structures are protected, but the fabrication process becomes more complex
Solution Approach 1:
The underlayer etch stop structure serves multiple functions: it acts as a selective barrier during sacrificial layer removal, provides a defined interface for nanowire formation, and can serve as a subsequent processing reference layer. This multi-functionality justifies the additional fabrication step by consolidating several requirements into one structure.
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 use of underlayer etch stops effectively prevents damage to source and drain structures, ensuring reliable fabrication of nanowire transistors by maintaining structural integrity and preventing shorting issues, thus enhancing the performance and reliability of nanowire-based microelectronic devices.
Implementation Method 1
Incorporating an underlayer etch stop structure that is selective to the sacrificial materials, allowing for their removal without damaging the source and drain structures
Data Source
AI summary
A nanowire device of the present description may be produced with the incorporation of at least one underlayer etch stop formed during the fabrication of at least one nanowire transistor in order to assist in protecting source structures and/or drain structures from damage that may result from fabrication processes. The underlayer etch stop may prevent damage to the source structures and/or drain the structures, when the material used in the fabrication of the source structures and/or the drain structures is susceptible to being etched by the processes used in the removal of the sacrificial materials, i.e. low selectively to the source structure and/or the drain structure materials, such that potential shorting between the transistor gate electrodes and contacts formed for the source structures and/or the drain structures may be prevented.