Buried Conductive Structure With Metal Capping for Low Resistance
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Solution Overview
Problem
The increasing demand for higher storage capacity, faster processing, and lower costs in semiconductor technology has led to challenges in reducing the resistance of buried conductive structures in semiconductor devices, which affects device performance.
Innovation Solution
The formation of metal capping layers below the bottom silicide layers using an atomic layer deposition (ALD) or chemical vapor deposition (CVD) process prevents oxidation and maintains the thickness of the bottom silicide layers, thereby reducing the resistance of buried conductive structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fabrication processes are used without metal capping layers, then the process is simpler, but the bottom silicide layers oxidize and resistance increases
Solution Approach 1:
Metal capping layers are formed on the bottom silicide layers before subsequent fabrication steps to prevent oxidation. This preliminary protective action ensures the silicide layers maintain their low-resistance properties throughout the fabrication process, resolving the contradiction between reliability and process complexity.
Solution Approach 2:
The metal capping layer acts as an intermediary protective barrier between the bottom silicide layer and the oxidizing environment. This intermediary layer prevents direct contact between oxygen and the silicide, maintaining electrical conductivity while allowing the fabrication process to proceed.
2Reliability
If metal capping layers are formed using ALD or CVD processes, then oxidation is prevented and resistance is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent specifies particular thickness ranges for the metal capping layers (e.g., 1-10 nm) and uses established ALD/CVD processes with controlled parameters. By optimizing these parameters, the patent achieves effective oxidation protection with minimal impact on manufacturing ease, balancing reliability improvements with manufacturing considerations.
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 results in low resistance buried conductive structures, enhancing the performance of semiconductor devices by maintaining the thickness of the bottom silicide layers and preventing oxidation.
Implementation Method 1
The formation of metal capping layers below the bottom silicide layers using an atomic layer deposition (ALD) or chemical vapor deposition (CVD) process prevents oxidation
Implementation Method 2
The formation of metal capping layers below the bottom silicide layers using an atomic layer deposition (ALD) or chemical vapor deposition (CVD) process prevents oxidation
Data Source
AI summary
The present disclosure describes a buried conductive structure in a semiconductor substrate and a method for forming the structure. The structure includes an epitaxial region disposed on a substrate and adjacent to a nanostructured gate layer and a nanostructured channel layer, a first silicide layer disposed within a top portion of the epitaxial region, and a first conductive structure disposed on a top surface of the first silicide layer. The structure further includes a second silicide layer disposed within a bottom portion of the epitaxial region and a second conductive structure disposed on a bottom surface of the second silicide layer and traversing through the substrate, where the second conductive structure includes a first metal layer in contact with the second silicide layer and a second metal layer in contact with the first metal layer.