Ion Beam Implantation Angle Range for Stable Crystal Channeling
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Solution Overview
Problem
Existing ion beam implantation methods face challenges in accurately aligning substrates to crystal channel directions, leading to variations in dopant ion penetration depths and distribution, which affects the formation of doped regions in semiconductor devices.
Innovation Solution
An ion beam implantation method that orients substrates within a specific angular tolerance interval, using an ion beam that implants dopant ions at angles within a controlled range relative to the target axis, ensuring effective channeling and consistent dopant distribution across the substrate, thereby decoupling the channeling effect from exact angular misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the ion beam direction is precisely aligned to the crystal channel direction, then the dopant ions achieve deeper penetration and form doped regions at greater depths, but the manufacturing precision and alignment complexity increase significantly
Solution Approach 1:
The patent changes the angular parameter from a single precise value to a range of values (±0.5° tolerance interval). By defining an angular tolerance interval rather than requiring exact alignment, the method maintains the channeling effect while reducing alignment precision requirements, thus resolving the contradiction between penetration depth and manufacturing precision
Solution Approach 2:
The patent introduces dynamic adjustment capability by allowing the ion beam direction to vary within the angular tolerance interval. The implantation process can accommodate deviations by adjusting the beam angle dynamically, maintaining effective channeling while simplifying alignment requirements
2Ease of manufacture
If the ion beam direction deviates from the crystal channel direction, then the alignment process becomes simpler, but the dopant ions experience reduced channeling effect and shallower penetration depth
Solution Approach 1:
The patent transforms the angular parameter from a critical single value to a tolerant range. By specifying that the angle between the ion beam axis and crystal channel direction should be within ±0.5°, the method maintains effective channeling while significantly easing the manufacturing and alignment process
Solution Approach 2:
The patent accepts a controlled deviation from perfect alignment as a tolerable imperfection. By defining an angular tolerance interval, the method allows for practical alignment imperfections without significantly compromising the channeling effect, making the process more robust and easier to manufacture
3Manufacturing precision
If a narrow angular tolerance interval is used for precise channeling, then the dopant distribution is more controlled, but the process sensitivity to misalignment increases and reproducibility decreases
Solution Approach 1:
The patent optimizes the angular tolerance interval to ±0.5°, which is wide enough to accommodate alignment variations and maintain process reproducibility, yet narrow enough to preserve effective channeling. This parameter optimization resolves the contradiction between precision control and process stability
Solution Approach 2:
The patent implies a feedback mechanism by defining a specific angular tolerance interval that compensates for alignment variations. The tolerance interval acts as a buffer that maintains consistent dopant distribution even when alignment conditions vary, improving process reliability
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 method enables the formation of doped regions with precise control over dopant concentration profiles, allowing for deeper penetration and reduced energy usage, while maintaining process stability and reproducibility across various substrates and implantation apparatuses.
Implementation Method 1
If the direction of the dopant ions is approximately parallel to a major crystal direction, the dopant ions undergo to a high degree only small-angle scattering as the dopant ions pass through the crystal lattice. The dopant ions remain in the same crystal channel ('channeling') and can penetrate deeper into the crystalline substrate
Implementation Method 2
If the direction of dopant ions incident upon the surface of a monocrystalline substrate is sufficiently tilted to major crystal directions in the substrate, the dopant ions predominately undergo large-angle scattering determining the final mean penetration depth of the dopant ions
Data Source
AI summary
In an example, a substrate is oriented to a target axis, wherein a residual angular misalignment between the target axis and a preselected crystal channel direction in the substrate is within an angular tolerance interval. Dopant ions are implanted into the substrate using an ion beam that propagates along an ion beam axis. The dopant ions are implanted at implant angles between the ion beam axis and the target axis. The implant angles are within an implant angle range. A channel acceptance width is effective for the preselected crystal channel direction. The implant angle range is greater than 80% of a sum of the channel acceptance width and twofold the angular tolerance interval. The implant angle range is smaller than 500% of the sum of the channel acceptance width and twofold the angular tolerance interval.