Self-limiting Selective Epitaxy for Semiconductor Fin Isolation
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Solution Overview
Problem
The challenge in semiconductor manufacturing is controlling the uniform growth of epitaxially deposited material on semiconductor fins to prevent electrical shorting between neighboring fins, as inherent variations in pitch, shape, and surface conditions lead to merging of raised active regions, creating undesirable conductive paths.
Innovation Solution
A self-limiting selective epitaxy process is employed, where the growth of semiconductor material is limited by crystallographic facets, ensuring that growth terminates when facets adjoin each other or a dielectric surface, preventing material merger and maintaining the dimensions of raised active regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If selective epitaxy is performed to grow semiconductor material on fins, then additional semiconductor material is provided to each fin, but merging between neighboring raised active semiconductor regions occurs due to uncontrolled growth
Solution Approach 1:
The patent changes the chemical parameters of the epitaxial growth process by introducing a chlorine-containing compound as a reactive ion beam source. This parameter change modifies the growth mechanism to be self-limiting, where the growth rate naturally decreases as the raised active regions grow, preventing merging while still adding material to each fin
Solution Approach 2:
The patent implements a feedback mechanism where the growth rate of the epitaxial material is automatically regulated by the presence of crystal facets. As the raised active regions grow and facets form, the reactive ion beam interaction with these facets creates a natural feedback loop that limits further growth, preventing merger between neighboring regions
2Productivity
If epitaxial growth rate is increased to provide more semiconductor material, then productivity improves, but merging between neighboring fins occurs due to high growth rate facets
Solution Approach 1:
The patent changes the physical state and chemical composition parameters of the depositing material by using a chlorine-containing compound delivered via reactive ion beam. This creates a self-regulating growth process where high growth rate facets are naturally suppressed, allowing fast deposition without causing merging between fins
Solution Approach 2:
The patent employs a self-service mechanism where the crystal facets themselves serve to limit growth. The facets that would normally cause high growth rates and merging instead become self-limiting boundaries, with the reactive ion beam automatically interacting with facet surfaces to prevent overgrowth and maintain electrical isolation
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 method effectively prevents the formation of conductive paths between semiconductor fins by controlling the growth of semiconductor material, ensuring uniformity and preventing electrical shorting, while providing additional semiconductor material to each fin.
Implementation Method 1
A plurality of faceted semiconductor material portions are grown on semiconductor surfaces of the at least one semiconductor fin by flowing at least one reactant precursor for the second single crystalline semiconductor material and an etchant in a selective epitaxy process
Implementation Method 2
flowing at least one reactant precursor for the second single crystalline semiconductor material and an etchant in a selective epitaxy process performed in a process chamber
Implementation Method 3
flowing at least one reactant precursor for the second single crystalline semiconductor material and an etchant in a selective epitaxy process
Data Source
AI summary
A self-limiting selective epitaxy process can be employed on a plurality of semiconductor fins such that the sizes of raised active semiconductor regions formed by the selective epitaxy process are limited to dimensions determined by the sizes of the semiconductor fins. Specifically, the self-limiting selective epitaxy process limits growth of the semiconductor material along directions that are perpendicular to crystallographic facets formed during the selective epitaxy process. Once the crystallographic facets become adjoined to one another or to a dielectric surface, growth of the semiconductor material terminates, thereby preventing merger among epitaxially deposited semiconductor materials.