Thin-Wire Ion Guide Structure for Higher Beam Current
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Solution Overview
Problem
Ion beam deposition systems face limitations in yield due to low ion beam intensity, leading to slow deposition speeds, which is a result of the limited current capacity of existing ion guides.
Innovation Solution
The use of a thin electrode wire ion guide with a plurality of elongate electrodes arranged around a longitudinal axis, supported by holding structures with specific resistivity characteristics to minimize charging and maintain tension, allowing for increased current capacity without increasing the ion guide diameter, thus enhancing the ion beam's guiding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional rod electrodes are used in ion guides, then the structure is simple and easy to manufacture, but the current capacity is limited and ion beam intensity is low
Solution Approach 1:
The patent divides the conventional rod electrode into multiple thin wire electrodes arranged in a multipole configuration. Instead of using a single thick rod, the electrode structure is segmented into numerous thin wires (e.g., 6-12 wires per pole), which increases the surface area and current capacity while maintaining the multipole field geometry. This segmentation allows higher ion beam intensity without compromising the guiding function.
Solution Approach 2:
The patent transitions from a two-dimensional rod cross-section to a three-dimensional wire array configuration. By arranging thin wires in a multipole pattern around the ion beam path, the system adds spatial dimensionality to the electrode structure, enabling increased current capacity through distributed wire surfaces rather than relying on a single rod surface.
2Quantity of substance
If the ion guide diameter is increased to accommodate more electrodes, then the current capacity increases, but the system size and gas load increase
Solution Approach 1:
The patent uses thin wire electrodes instead of thick rods, creating a flexible, space-efficient electrode structure. The thin wires can be arranged densely in a multipole configuration within a compact diameter, maximizing current capacity without proportionally increasing the ion guide volume. The thin film-like surface area of multiple wires provides high current capacity in a confined space.
Solution Approach 2:
The patent changes the geometric parameters of the electrodes from thick rods to thin wires, and adjusts the wire diameter and spacing to optimize current capacity within a fixed ion guide diameter. By controlling wire thickness (e.g., 0.5-2 mm diameter) and inter-wire distances, the system achieves high current capacity without increasing the overall ion guide volume.
3Quantity of substance
If thin electrode wires are used, then the current capacity increases, but the wires may bend or deform under tension
Solution Approach 1:
The patent applies preliminary tension to the thin wire electrodes during installation to pre-straighten them and maintain their positional stability. By applying tension before operation, the wires are held in their intended straight configuration, preventing bending or deformation during ion guide operation while maintaining the high surface area-to-volume ratio that provides high current capacity.
Solution Approach 2:
The patent applies different mechanical properties to different parts of the wire support structure. The wires themselves remain thin for high current capacity, while the support points and mounting structures provide localized reinforcement and tension application. This local differentiation allows thin wires to maintain straightness through targeted support without requiring the entire wire structure to be thick or rigid.
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 design significantly increases the yield of the ion beam deposition system by optimizing the current capacity through a higher number of thin electrodes and appropriate resistivity materials, reducing gas load and ion losses while maintaining efficient ion guidance.
Implementation Method 1
systems of electrodes can be employed which are driven with radio frequency (RF) voltages having frequencies of about 0.5 to 5 MHz and amplitudes of some volts up to some 100 volts. When the amplitude and the frequency of the RF potential are properly chosen, ions will be effectively repelled from the RF electrodes by means of an effective potential or 'pseudo-potential' which reflects the effect of the RF electric field on the ion averaged over a plurality of AC cycles.
Implementation Method 2
any portion of said holding structures which is separated from said ion guide volume by less than the local inter-wire distance, preferably by less than twice the local inter-wire distance, and most preferably by less than three times the local inter-wire distance is made from a material having a resistivity of less than 10^12 Ωcm
Data Source
Figure 1
Figure 2~3
Figure 3a
AI summary
Disclosed herein is an ion guide (36) for guiding an ion beam along an ion path, said ion guide (36) having a longitudinal axis (44) corresponding to said ion path, said ion guide (36) comprising a plurality of elongate electrodes arranged around and extending along said longitudinal axis (44), wherein an inner envelope (120) of the plurality of electrodes defines an ion guide volume (128). Said elongate electrodes are formed by electrode wires (42), wherein adjacent electrode wires (42) are arranged at an inter-wire distance (122). The ion guide (36) comprises holding structures for supporting and for straightening the electrode wires (42) by applying a tension or maintaining a tension applied to them. Any portion of said holding structures which is separated from said ion guide volume by less than the local inter-wire distance (122) is made from a material having a resistivity of less than 1012 Ohm·cm, preferably of less than 109 Ohm·cm, or has a sheet resistivity of less than 1014 Ohm, preferably of less than 1010 Ohm on a surface facing said ion guide volume (128).