Nano-Aperture Ion Microscope for High-Brightness Proton Beams
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Solution Overview
Problem
Current Proton Beam Writing (PBW) and Ion Beam Induced Charge (IBIC) systems are limited by low reduced brightness of radio frequency (RF) ion sources, which restricts their performance in terms of spot size and throughput, and existing ion sources are not designed to produce high brightness proton beams necessary for improved resolution and throughput.
Innovation Solution
A nano-aperture ion source (NAIS) with an electron direct impact ionization mechanism is used, capable of generating high brightness proton beams by selectively coaxially focusing an ion beam generated from an electron beam ionizing an ionizing gas, employing electrostatic lenses such as Einzel lenses or quadrupole lenses for focusing, allowing for sub-10 nm beam spot sizes and high beam currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radio frequency (RF) ion source is used in current PBW systems, then the system can operate with available technology, but the reduced brightness is low (∼20 A/(m2srV)) which limits spot size and throughput performance
Solution Approach 1:
The patent changes the fundamental parameters of the ion source by transitioning from RF ionization to electron beam impact ionization in a nano-aperture configuration. This parameter change increases reduced brightness from ∼20 A/(m2srV) to >10^5 A/(m2srV), simultaneously improving both spot size and throughput performance while maintaining technological feasibility.
2Device complexity
If conventional ion sources are used, then the system structure is simpler, but the brightness is insufficient to achieve sub-10 nm beam spot sizes required for improved resolution
Solution Approach 1:
The patent segments the ion generation process into distinct components: electron beam generation, ionization chamber with nano-aperture, and extraction region. This segmentation allows each component to be optimized independently, achieving sub-10 nm beam spot sizes through precise control of the ionization and extraction processes while managing overall system complexity.
Solution Approach 2:
The patent introduces an intermediary nano-aperture structure that mediates between the electron beam ionization process and the ion extraction system. This intermediary component enables high brightness ion beam generation by controlling the ionization region geometry and facilitating efficient ion extraction, thereby achieving improved resolution without excessive system complexity.
3Productivity
If high beam current is achieved with conventional sources, then throughput improves, but spot size increases due to space charge effects and source limitations
Solution Approach 1:
The patent changes the brightness parameter by implementing electron beam impact ionization with a nano-aperture, which decouples the relationship between beam current and spot size. This allows high beam currents to be achieved while maintaining small spot sizes, overcoming the space charge limitations of conventional ion sources through fundamental parameter changes in the ionization mechanism.
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 significantly improves the resolution and throughput of PBW and IBIC, enabling precise ion implantation and fabrication of nano-structures with sub-10 nm resolution, addressing the limitations of existing technologies by achieving writing speeds comparable to electron beam lithography without proximity effects.
Implementation Method 1
an electron beam ionizing an ionizing gas in the nano-aperture ion source
Implementation Method 2
employing electrostatic lenses such as Einzel lenses or quadrupole lenses for focusing
Data Source
AI summary
An ion microscope, a method of constructing an ion microscope, and a method of aligning an ion beam in an ion microscope. The microscope comprises a nano-aperture ion source; and a focusing system; wherein the focusing system is configured for selectively coaxially focusing an ion beam generated from an electron beam ionizing an ionizing gas in the nano-aperture ion source and the electron beam.