Crystalline Inner Spacer Structure for Void-Free Nanosheet Source/Drain
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Solution Overview
Problem
In semiconductor devices, the formation of voids between inner spacers and source/drain regions can occur when amorphous insulating materials are used, leading to reliability issues.
Innovation Solution
The use of crystalline insulating materials, such as crystalline aluminum nitride, for the inner spacer allows for epitaxial growth of the source/drain region, preventing void formation and enhancing device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous insulating materials are used for the inner spacer, then the manufacturing process is simpler, but voids form between the inner spacer and source/drain region
Solution Approach 1:
The patent changes the physical state parameter of the insulating material from amorphous to crystalline. This parameter change enables epitaxial growth of the source/drain region on the inner spacer surface, preventing void formation and improving device reliability while maintaining manufacturing feasibility
Solution Approach 2:
The patent uses a composite structure where the inner spacer is made of crystalline insulating material (such as crystalline silicon nitride or crystalline silicon oxide) that provides a suitable surface for epitaxial growth. This composite approach combines the insulating properties with the epitaxial growth capability, resolving the contradiction between ease of manufacture and reliability
2Reliability
If crystalline insulating materials are used for the inner spacer, then epitaxial growth occurs preventing void formation, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by forming the inner spacer with crystalline insulating material before the source/drain region formation step. This preliminary preparation of the spacer surface enables subsequent epitaxial growth without requiring additional complex processes, as the crystalline structure is already in place to support the epitaxial growth of silicon
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 implementation of crystalline insulating materials in inner spacers ensures the epitaxial growth of the source/drain region, inhibiting void formation and improving the reliability of semiconductor devices.
Implementation Method 1
an inner spacer is made of a crystalline insulating material such that a source/drain region epitaxially grows from the inner spacer, thereby inhibiting or preventing formation of a void between the inner spacer and the source/drain region
Data Source
AI summary
A semiconductor device includes a substrate, an active pattern on the substrate, the active pattern extending in a first horizontal direction, a first plurality of nanosheets on the active pattern, the first plurality of nanosheets stacked and spaced apart from each other in a vertical direction, and a gate electrode on the active pattern. The gate electrode extends in a second horizontal direction different from the first horizontal direction, and the gate electrode surrounds the first plurality of nanosheets. The semiconductor device includes an inner spacer on at least one side surface of the gate electrode, the inner spacer between adjacent ones of the first plurality of nanosheets, and the inner spacer including a crystalline insulating material.