Fluorine-Doped Regions Impede Dopant Diffusion in Semiconductor Junctions
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Solution Overview
Problem
Conventional semiconductor device fabrication processes, such as thermal annealing, lead to undesirable dopant diffusion, affecting the electrical properties of memory devices due to the inability to maintain precise dopant concentration profiles.
Innovation Solution
A method involving the formation of fluorine-doped regions at junctions within semiconductor structures, which impedes dopant diffusion during thermal treatment, allowing for the creation of semiconductor devices with improved electrical properties by preventing dopant migration between regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermal treatment processes are employed to form conventional access devices, then the semiconductive material can be processed and devices can be formed, but dopant diffusion occurs that undesirably alters the locations of implanted dopant species
Solution Approach 1:
The patent applies preliminary action by forming a protective oxide layer on the semiconductor substrate before thermal treatment. This oxide layer is created in advance to prevent dopant diffusion during subsequent thermal processing steps, thereby preserving the implanted dopant concentration profile while still allowing thermal treatment to proceed for device formation
Solution Approach 2:
The patent uses an oxide layer as an intermediary barrier between the implanted dopants and the thermal treatment process. This intermediate layer physically separates the dopants from the thermal environment, preventing direct interaction that would cause unwanted diffusion while still permitting the thermal processing necessary for device fabrication
2Reliability
If dopants are implanted to form source/drain regions, then the access device can be formed with desired electrical properties, but thermal treatment causes dopants to diffuse into other regions altering the concentration profile
Solution Approach 1:
The oxide layer is formed preliminarily before thermal treatment to lock in the dopant concentration profile. This pre-formed protective layer ensures that the electrical properties achieved through precise dopant implantation are maintained throughout subsequent thermal processing, preventing composition drift
Solution Approach 2:
The oxide layer serves as a mediating barrier that allows thermal treatment to proceed for device formation while simultaneously protecting the dopant concentration profile from diffusion. This intermediary structure decouples the thermal processing requirement from the dopant stability requirement, enabling both to be satisfied
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 enhances the performance, efficiency, reliability, and durability of semiconductor devices by maintaining desired dopant profiles and reducing junction leakage and channel resistance.
Implementation Method 1
a fluorine-doped region is formed at junctions between the well region and additional regions of the semiconductive structure vertically overlying the well region. During the thermal treatment process, the fluorine-doped region impedes the dopants within the well region of the semiconductive structure from diffusing into the additional regions
Data Source
AI summary
A method of forming an apparatus comprises forming filled trenches within a semiconductive structure having a well region comprising one or more dopants, the filled trenches extending into the well region and each individually comprising a conductive gate structure and a dielectric liner intervening between the conductive gate structure and the semiconductive structure. A fluorine-doped region is formed at junctions between the well region and additional regions of the semiconductive structure overlying the well region. The additional regions of the semiconductive structure are doped with one or more additional dopants having a different conductivity type than that of the one or more dopants of the well region after forming the fluorine-doped region. The semiconductive structure is annealed after doping the additional regions thereof. Apparatuses, memory devices, and electronic systems also described.