Crystalline Source-Drain Contacts via Selective Precursor Deposition
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Solution Overview
Problem
Current methods for forming source and drain contacts in semiconductor devices, such as FinFETs, face challenges including high contact resistance, variability in contact thickness, and the risk of electrical shorts due to non-uniform deposition and high-temperature processing of elemental metals, which affect the performance and reliability of integrated circuit devices.
Innovation Solution
The formation of crystalline source and drain contacts by selectively depositing precursors on exposed surfaces of the semiconductor device, which react in situ to form conformal, low-resistance contacts, eliminating the need for blanket elemental metal deposition and high-temperature processing, thereby reducing contact resistance and improving uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If blanket elemental metal deposition is used to form source and drain contacts, then contact formation is achieved, but contact resistance is high and contact thickness varies non-uniformly
Solution Approach 1:
The patent applies local quality by selectively depositing metal precursors only on the source and drain regions rather than blanket deposition across the entire substrate. This localized approach ensures uniform contact thickness only where contacts are needed, eliminating the non-uniformity inherent in blanket deposition while maintaining low contact resistance through precise material placement
Solution Approach 2:
The patent changes the deposition parameters by using atomic layer deposition (ALD) with precursors that react in-situ at lower temperatures. This parameter change from conventional high-temperature elemental metal deposition to low-temperature precursor deposition enables better control over contact thickness uniformity and reduces contact resistance through more uniform material distribution
2Reliability
If high-temperature processing is used to form elemental metal contacts, then contact formation is achieved, but variability in contact thickness increases
Solution Approach 1:
The patent changes the temperature parameter by using low-temperature precursor deposition instead of high-temperature elemental metal processing. This parameter change reduces thermal diffusion and material redistribution that cause thickness variability, while still achieving reliable contact formation through the reactive deposition process
Solution Approach 2:
The patent substitutes the mechanical/thermal process of high-temperature elemental metal deposition with a chemical vapor deposition process using precursors. This substitution replaces the high-temperature mechanism with a lower-temperature chemical reaction mechanism that provides better control over contact thickness and reduces variability
3Productivity
If non-uniform deposition is used to form contacts, then deposition speed is maintained, but electrical shorts occur due to poor contact uniformity
Solution Approach 1:
The patent applies local quality by using selective deposition that targets only the source and drain regions with precise spatial control. This ensures uniform contact formation locally at each contact site, preventing the electrical shorts that result from non-uniform deposition, while maintaining productivity through the efficiency of targeted material placement
Solution Approach 2:
The patent implements feedback control through the ALD process, where each deposition cycle can be precisely controlled and monitored. This feedback mechanism ensures uniform contact thickness is achieved at each location, preventing electrical shorts while maintaining deposition speed through optimized cycle parameters
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 decreases contact resistance, enhances transistor switching speed, reduces power consumption, and minimizes the risk of electrical shorts, leading to improved performance and manufacturing yields of integrated circuit devices with reduced variability in contact thickness across the substrate.
Implementation Method 1
selectively depositing precursors on exposed surfaces of the semiconductor device, which react in situ to form conformal, low-resistance contacts
Data Source
AI summary
Techniques for forming contacts comprising at least one crystal on source and drain (S/D) regions of semiconductor devices are described. Crystalline S/D contacts can be formed so as to conform to some or all of the top and side surfaces of the S/D regions. Crystalline S/D contacts of the present disclosure are formed by selectively depositing precursor on an exposed portion of one or more S/D regions. The precursor are then reacted in situ on the exposed portion of the S/D region. This reaction forms the conductive, crystalline S/D contact that conforms to the surface of the S/D regions.