FinFET Channel Stop Imp via Isolation Etch Back
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Solution Overview
Problem
The short channel effect and punch through effect in FinFET devices become significant issues as feature sizes decrease, with dopants diffusing into the channel region during the annealing process after channel stop ion implantation, affecting device performance.
Innovation Solution
A method is developed to reduce dopant diffusion into the channel region by performing an etch back process on the isolation region before annealing, allowing dopants to diffuse outside the isolation region and semiconductor fins, thereby minimizing their impact on the channel region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If channel stop ion implantation is performed to suppress punch through effect, then device reliability is improved, but dopants diffuse into channel region during annealing causing harmful effects
Solution Approach 1:
The patent applies preliminary action by performing channel stop ion implantation before the annealing process, ensuring dopants are positioned in the isolation region prior to thermal treatment. This sequencing allows the implantation to occur when the structure is intact, preventing subsequent dopant migration into the channel during annealing.
Solution Approach 2:
The patent extracts the dopants from the channel region by directing ion implantation specifically into the isolation region. The dopants are taken out of potential harm to the channel and placed into the isolation region where they can be activated during annealing without affecting channel performance.
2Length of moving object
If feature size is reduced to improve device scaling, then device size is decreased, but short channel effect and punch through effect become more significant
Solution Approach 1:
The patent applies preliminary anti-action by introducing channel stop doping into the isolation region before channel formation issues can develop. This preemptive doping creates a protective effect against short channel and punch through effects that would otherwise become more severe with reduced feature sizes.
Solution Approach 2:
The patent applies local quality by concentrating dopants specifically in the isolation region adjacent to the channel, rather than uniformly throughout the structure. This localized doping provides targeted suppression of punch through effects at the critical isolation-channel interface while maintaining channel integrity.
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 dopant diffusion into the channel region, enhancing the performance of FinFET devices by mitigating the short channel and punch through effects.
Implementation Method 1
implanting ions into the substrate structure to form a doped region in the at least one semiconductor fin and in the isolation region
Implementation Method 2
performing an annealing process to activate the implanted ions in the doped region
Implementation Method 3
etching back the isolation region to expose a portion of the at least one semiconductor fin
Data Source
AI summary
A method for manufacturing a semiconductor device includes providing a substrate structure including a substrate, a semiconductor fin on the substrate, and an isolation region on opposite sides of the semiconductor fin, the isolation region having an upper surface substantially flush with an upper surface of the at least one semiconductor fin. The method also includes implanting ions into the substrate structure to form a doped region in the semiconductor fin and in the isolation region, etching back the isolation region to expose a portion of the semiconductor fin, and performing an annealing process to activate the implanted ions in the doped region. Because the annealing is performed after the etching back of the isolation region, a portion of the implanted ions diffuses out of the isolation region and the fin, thereby reducing ion diffusion into the channel region and improving the device performance.