Halogen Metal Cap Layers for Low-Resistance FinFET Contacts
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in achieving low gate and contact resistance as device scaling-down continues, particularly in protecting gate electrode and contact structures during etching processes.
Innovation Solution
The use of halogen-containing metal cap layers, specifically a first halogen-containing metal cap layer on the gate electrode and a second halogen-containing metal cap layer on the contact structure, formed using different precursor gases to prevent damage and ensure low resistance, with the second cap layer using a fluoride-containing precursor gas to reduce oxygen content at interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing processes are used, then device scaling-down continues, but gate and contact resistance cannot be sufficiently reduced
Solution Approach 1:
A metal cap layer is introduced as an intermediary protective layer between the gate electrode layer and the etching environment. This cap layer acts as a mediator that prevents direct exposure of the gate electrode to harmful etching conditions, thereby reducing gate resistance while protecting the underlying structure during subsequent etching processes
Solution Approach 2:
The metal cap layer is formed in advance before the etching process. This preliminary protective action ensures that the gate electrode layer is already protected before exposure to etching chemicals, preventing damage and ensuring low resistance pathways are established prior to subsequent processing steps
2Ease of manufacture
If a single halogen-containing precursor gas is used, then deposition is simplified, but oxygen content at interfaces cannot be minimized
Solution Approach 1:
The deposition process is segmented into two distinct stages using two different halogen-containing precursor gases. The first precursor gas deposits the initial metal cap layer, while the second precursor gas deposits an additional layer with different chemical properties. This segmentation allows each layer to contribute differently to interface quality, minimizing oxygen content while maintaining manufacturing feasibility
Solution Approach 2:
The metal cap structure is formed as a composite of two different metal layers deposited from different halogen-containing precursors. This composite structure combines the benefits of both materials, where the first layer provides base protection and the second layer optimizes interface properties by reducing oxygen content, achieving superior electrical characteristics
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 approach effectively reduces gate and contact resistance by protecting the structures during subsequent processes and minimizing defects, thereby improving the performance of semiconductor structures.
Implementation Method 1
formed using different precursor gases
Implementation Method 2
the second cap layer using a fluoride-containing precursor gas to reduce oxygen content at interfaces
Data Source
AI summary
Semiconductor structures and method for forming the same are provided. The semiconductor structure includes a fin protruding from a substrate and a gate stack formed across the fin. The semiconductor structure further includes a source/drain structure attaching to the gate stack and a contact structure connecting to the source/drain structure. The semiconductor structure further includes a first cap layer covering a top surface of the contact structure. In addition, the first cap layer includes a first halogen.