Semiconductor Silicide Fabrication for Oxygen Cluster Removal
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Solution Overview
Problem
Current semiconductor fabrication methods for radio frequency silicon-on-insulator (RFSOI) devices face issues with high resistance due to oxygen cluster accumulation in the substrate, which affects device performance.
Innovation Solution
A method involving a first cleaning process and a first rapid thermal anneal (RTA) process to remove oxygen clusters in the substrate before silicide formation, followed by a second RTA process to transform a metal layer into a silicide layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional polysilicon gate is used for fabricating MOS transistor, then gap-filling capability is achieved, but device performance deteriorates due to boron penetration and depletion effect
Solution Approach 1:
The patent extracts and removes the harmful elements (oxygen clusters) from the substrate before silicide formation. By performing cleaning and RTA processes to eliminate oxygen clusters prior to metal layer deposition and silicidation, the invention prevents the formation of high-resistance regions while maintaining the benefits of conventional fabrication approaches.
Solution Approach 2:
The patent applies preliminary cleaning and RTA processes before the main silicide formation step. By removing oxygen clusters in advance (preliminary action) through cleaning and thermal annealing before metal deposition and silicidation, the invention prevents future resistance issues rather than addressing them after formation.
2Device complexity
If oxygen cluster accumulation is not prevented during fabrication, then manufacturing process is simplified, but device resistance increases
Solution Approach 1:
The patent segments the fabrication process into distinct stages: cleaning process, first RTA process for oxygen cluster removal, metal layer formation, and second RTA process for silicide formation. This segmentation allows targeted removal of oxygen clusters at specific process stages, preventing resistance issues without overly complicating the overall fabrication flow.
Solution Approach 2:
The patent utilizes parameter changes in the RTA process (temperature, time, atmosphere) to remove oxygen clusters and transform metal layers into silicide layers. By controlling thermal parameters during annealing, the invention achieves oxygen cluster elimination and silicide formation without significantly increasing process complexity.
3Reliability
If rapid thermal anneal process is performed before silicide formation, then oxygen clusters are removed and resistance is reduced, but process time and temperature cycles increase
Solution Approach 1:
The patent merges the oxygen cluster removal function with the necessary preparatory steps before silicide formation. By integrating cleaning and RTA processes into the pre-silicidation sequence, the invention achieves resistance reduction without adding significant standalone process time, as these steps are necessary preparatory actions anyway.
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 method effectively reduces overall resistance in the device by preventing oxygen cluster accumulation, thereby enhancing device performance and reliability.
Implementation Method 1
performing a first rapid thermal anneal (RTA) process to remove oxygen cluster in the substrate
Implementation Method 2
performing a second RTA process to transform the metal layer into a silicide layer
Data Source
AI summary
A method for fabricating a semiconductor device includes the steps of: forming a gate structure on a substrate; forming a source/drain region adjacent to the gate structure; performing a first cleaning process; performing a first rapid thermal anneal (RTA) process to remove oxygen cluster in the substrate; forming a metal layer on the source/drain region; and performing a second RTA process to transform the metal layer into a silicide layer.