Inputs
Example Data Table
| Ion → Target | Energy (eV) | Angle (deg) | Us (eV) | Model | Typical Yield (atoms/ion) |
|---|---|---|---|---|---|
| Ar (18, 39.95) → Cu (29, 63.546) | 5000 | 0 | 3.5 | Threshold model | ~0.5–3 (setup dependent) |
| Ar (18, 39.95) → Si (14, 28.085) | 1000 | 45 | 4.7 | Simplified scaling | ~0.1–1.5 (setup dependent) |
| Xe (54, 131.29) → Au (79, 196.97) | 10000 | 60 | 3.8 | Threshold model | ~1–10 (setup dependent) |
Formula Used
The calculator uses a compact analytical form inspired by Sigmund-type sputtering theory and a threshold-shaped extension. It is designed for fast, educational estimates rather than replacing detailed transport simulations.
- Y ≈ K · α(M1,M2) · Sn(E,Z1,Z2) / Us · F(θ)
- F(θ) = (1 / cos θ)p, capped near grazing incidence
- Eth ≈ Us · [1.5 + 2·|M1/M2 − 1|/(1+M1/M2)] (approx)
- Threshold model shape (if selected): Y ← Y · (1 − (Eth/E)2/3) · (1 − Eth/E)2 for E > Eth
Sn is estimated with a universal reduced-energy fit to keep inputs simple. If you already have stopping data, choose “Custom stopping” and enter Sn directly.
How to Use This Calculator
- Enter ion and target atomic numbers and masses.
- Set the ion energy in eV and incidence angle in degrees.
- Provide the surface binding energy Us for the target material.
- Select a model: threshold-shaped for planning, or simplified scaling.
- Fill beam current, area, density, and time to estimate thickness removed.
- Press Calculate to view results above the form.
- Use the download buttons to export CSV or PDF summaries.
Article
1) Sputter yield in practical terms
Sputter yield, Y, is the average number of atoms ejected per incident ion. For many metals under argon, Y sits around 0.2–5 atoms/ion from 300–5000 eV, depending on angle and binding energy. This calculator estimates Y for screening recipes.
2) Ion species and momentum transfer
Ion mass and atomic number shape how efficiently energy reaches near‑surface atoms. A closer mass match increases recoil density and raises Y. Ar (≈40 u) is efficient on mid‑mass targets, while heavier ions like Xe (≈131 u) can boost sputtering at the same voltage but may increase heating and implantation.
3) Energy range and threshold behavior
Many surfaces exhibit an effective threshold where sputtering becomes measurable. Compact models represent this with a threshold energy Eth tied to surface binding energy Us. If E is only slightly above Eth, Y can rise steeply with voltage. Typical operating windows span roughly 200–10000 eV.
4) Incidence angle and cascade geometry
Yield increases at oblique incidence because collision cascades broaden laterally and deposit more energy near the surface. Many systems peak near 50–70°. Near 80–85°, reflection and channeling can reduce deposition, so the calculator caps extreme angle growth for planning.
5) Material properties that matter
Surface binding energy and density affect predicted removal. Metals often use Us ≈2–5 eV, while covalent solids can be higher. Density enters only when converting atoms into thickness. For example, copper at 8.96 g/cm³ removes fewer nanometers per second than a lower‑density material at the same ion flux.
6) From electrical current to thickness rate
With singly charged ions, ion rate is I/e. A 2.0 mA beam is 1.25×1016 ions/s. The sputtered atom rate equals that value times Y. Using molar mass and density, the calculator converts to volume flow and divides by raster area to estimate nm/min and total thickness removed over time.
7) Managing uncertainty and calibration
Real yields vary with oxides, roughness, chemistry, redeposition, and charge state. Use this tool to set a first recipe, then calibrate with profilometry, ellipsometry, or a quartz crystal monitor. If you have stopping data, the custom stopping option can improve comparative consistency.
8) Reporting, consistency, and repeatability
Record ion species, energy, angle, current, area, and material constants with each run. CSV exports support lab notebooks and batch comparisons, while PDF summaries capture assumptions for process travelers. Consistent inputs and periodic calibration improve repeatability across tools and operators.
FAQs
1) What is sputter yield?
Sputter yield is the average number of target atoms removed per incoming ion. It is reported as atoms/ion and depends on ion species, energy, incidence angle, and surface bonding.
2) Why does my yield become zero?
If the selected model estimates a threshold energy higher than your ion energy, the predicted yield becomes zero. Increase energy, reduce Us if appropriate, or switch to the simplified scaling model for quick comparisons.
3) Which model should I choose?
Use the threshold model when you care about low‑energy behavior near onset. Use simplified scaling for fast trend checks. Use custom stopping when you already know stopping values from a trusted source or calibration.
4) What should I enter for Us?
Us is a practical surface binding parameter. Metals often use 2–5 eV, while harder covalent solids can be higher. If you have a measured sputter rate, tune Us so the calculator matches that reference point.
5) How is thickness rate estimated?
The tool converts current to ion rate using I/e, multiplies by yield to get atoms per second, then converts atoms to volume using molar mass and density. Dividing by beam area produces a thickness rate in nm/min.
6) Can I use this for compounds?
You can approximate compounds with effective Z, molar mass, and density, but preferential sputtering can change composition. For critical work, calibrate with measurements or use a compound‑aware database and enter custom stopping.
7) How should I validate results?
Start with one well‑characterized condition, measure removed thickness, and adjust inputs to match. Then vary one parameter at a time. Periodic checks with profilometry, ellipsometry, or QCM keep recipes consistent over time.