Tapered Grid Electrode Holes for Stable Charge Carrier Extraction
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Solution Overview
Problem
Conventional charge carrier beam sources experience instability due to wear-induced changes in the thickness of the first electrode, leading to increased charge carrier extraction current and reduced stability of the beam.
Innovation Solution
The charge carrier generation source incorporates a grid electrode with through-holes that have a larger opening surface on the side adjacent to the carrier generation area, which decreases to a smaller opening surface on the opposite side, compensating for wear-induced thickness reduction and maintaining a constant charge carrier current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first electrode is used with a uniform cylindrical through-hole, then the charge carrier extraction is initially stable, but wear of the electrode causes field strength changes and current instability
Solution Approach 1:
The through-holes are pre-configured with a tapered shape (larger opening at the plasma boundary side, smaller opening at the exit side) before wear occurs. This preliminary geometric configuration compensates for the thickness reduction that will occur during electrode service, maintaining constant charge carrier current extraction throughout the electrode's operational life.
Solution Approach 2:
The invention changes the geometric parameters of the through-holes from uniform cylindrical to tapered frustoconical shape. This parameter change in the hole geometry (varying cross-sectional area along the thickness direction) compensates for the wear-induced thickness reduction, keeping the effective extraction area constant over time.
2Power
If the electrode thickness is reduced by wear, then the field strength increases and charge carrier current increases, but beam stability is reduced
Solution Approach 1:
The tapered geometry of the through-holes provides a preliminary counteracting effect to the wear-induced field strength increase. As the electrode wears and thickness decreases, the corresponding reduction in through-hole cross-sectional area (due to the tapered shape) counterbalances the field strength increase, preventing excessive current increase and maintaining beam stability.
3Reliability
If the through-hole area is increased to compensate for wear, then current stability is maintained, but material removal rate increases
Solution Approach 1:
The invention optimizes the through-hole geometry parameters (tapered shape with specific opening areas at each end) to achieve current stability while minimizing unnecessary material removal. The tapered configuration allows the effective area to decrease with wear, compensating for field strength changes without requiring an initially larger hole area.
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 configuration effectively compensates for wear-induced changes, maintaining a constant charge carrier current and reducing the need for active regulation, thereby enhancing the stability and efficiency of the charge carrier beam source.
Implementation Method 1
On contact with the first electrode 16, the plasma forms a plasma boundary layer of defined thickness due to the charge carrier mobilities
Implementation Method 2
An electric potential Vt may be applied to the electrodes 14, 16 so that charge carriers may be extracted and accelerated or charge carrier (sub) beams may be blocked
Data Source
AI summary
A carrier generation source is provided, comprising a carrier generation area configured to provide carriers and a grid electrode, the grid electrode comprising an electrically conductive carrier, the carrier having a first side and a second side opposite the first side, the first side being directly adjacent the carrier generation area, the carrier having a plurality of through-holes extending from the first side through the carrier to the second side, the through-holes on the first side each having a first opening surface and the through-holes on the second side having a second opening surface, the first opening surface being larger than the second opening surface.