Effect of Secondary Electron Emission From Various Targets During Variable Pulse Length PIII
Bibliographic record
Abstract
Plasma Immersion Ion Implantation(PIII) is a versatile material processing technique [1] , [2] . In PIII a solid target is immersed in plasma, and negative-polarity high-voltage(NPHV) pulses are applied to the target. During a NPHV pulse electrons are repelled from the near-target region, resulting in a positive ion sheath surrounding the target; ions traversing the sheath are implanted into the target surface. Lieberman et al. [2] developed a PIII sheath model which captures basic aspects of the sheath evolution during PIII pulses. However, some key assumptions used in this model do not hold. In particular, experiments show that the plasma density and electron temperature do not remain constant during the NPHV pulses, due to various effects, including the effect of secondary electrons ejected from the target. The ejected electrons accelerate back through the sheath, depositing their energy in the bulk plasma; this can significantly increase the plasma density and electron temperature above the nominal steady-state values measured before the PIII pulse [3] , [4] , [5] . To further elucidate the effect of secondary electrons, we report on recent PIII experiments with variable pulse lengths(10us-100us) on a range of target materials including silicon, stainless steel, brass, and tungsten alloys with a range of NPHV pulse amplitudes(1-5 kV). We discuss the results of these experiments and the various mechanisms involved.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".