ULVAC Electron Beam Guns and Power Generators
ULVAC electron beam (EB) guns are used in physical vapour deposition (PVD) systems for thin film deposition by electron beam evaporation. An accelerated electron beam focuses onto source material in a water-cooled hearth, melting and evaporating the material to deposit films on substrates above. ULVAC manufactures the EGK, EGL, EGN, and EGO series guns, and the HPS series high-voltage power generators that supply the accelerating voltage and beam control.
Part Numbers
Safety
HIGH VOLTAGE WARNING. HPS power generators operate at up to 10 kV accelerating voltage. High-voltage interlocks must be verified before any access to the gun area. Implement lockout/tagout before any maintenance on the gun or power generator. Do not operate EB guns with chamber panels open or high-voltage interlocks defeated. The electron beam generates X-rays at the target — chamber walls must provide adequate shielding and the system must be interlocked to prevent operation when access panels are open.
Product Families
| Series | Description | Crucible Configuration |
|---|---|---|
| EGK-3, EGK-3M | Compact EB gun for small-scale deposition | Single or 4-crucible hearth |
| EGL-35, EGL-35M | Standard EB gun for optical and semiconductor coatings | Single, 10cc x2 + 40cc x2, 40cc x4, and other configurations |
| EGL-80M, EGL-110, EGL-206M | Larger EB guns for higher deposition rates | 4 to 6 crucible configurations |
| EGL-406M, EGL-103S | High-capacity large hearth guns | 6-crucible or 3-crucible |
| EGN-206M, EGN-406M, EGN-406M-N/SN | Hearth deck integral-type with reflection electron absorption mechanism | 6-crucible; straight-type filament variants |
| EGO-1G, EGO-40M, EGO-110M, EGO-206M, EGO-406M | EB guns optimised for optical evaporation applications | Single to 6-crucible configurations |
| EGO-ES2 | Electron shower gun for charge neutralisation on insulating substrates | N/A |
| HPS-510S, HPS-600N-100/200, HPS-1000N-100/200, HPS-1600F-S100/S200 | High-voltage EB power generators, 5 to 16 kW | 1 or 2 source configurations |
| EGC-10GS S-type and G-type | EB gun controller; LCB not included | N/A |
Operating Principle
A directly heated tungsten hairpin filament emits electrons when heated to emission temperature. These electrons are accelerated by the high-voltage field (6 to 10 kV) from the HPS power generator. A magnetic deflection coil bends the beam 270 degrees and focuses it onto the source material in the hearth. The focused beam heats the source material to its evaporation temperature. Material vapour condenses on the substrate above, forming the deposited film.
Commissioning Sequence
- Verify chamber at working vacuum before enabling high voltage — minimum 5e-3 Pa; never apply HV above 1e-3 Pa
- Verify interlock chain: chamber pressure interlock satisfied, door and panel interlocks satisfied, HV enable permissive satisfied
- Set HPS to minimum accelerating voltage and minimum emission current
- Filament conditioning: gradually increase filament current over 15 to 30 minutes to degas new filament
- Enable HV at minimum voltage; verify HV readback matches setpoint
- Increase emission current slowly; verify beam deflection coil current is correct
- Enable beam sweep; verify sweep pattern illuminates hearth evenly
- Increase beam power to process setpoint gradually — prevent thermal shock
- For multi-source guns: index hearth to each position; verify beam lands on each crucible correctly
- Record commissioning data: HV, emission current, filament current, sweep parameters, chamber pressure
Filament Maintenance
The tungsten hairpin filament is the primary consumable. Monitor filament current trend — rising filament current at constant emission current indicates thinning. Replace before it breaks. Key hearth part numbers: EGK-3 (210004014100), EGK-3M (210004014200), EGL-35 (210004014300), EGL-35M configurations (210004014400, 210004039200-210004039600), EGL-110/80 (210004014500), EGL-206M (210004014600), EGN-206M crucible (210006800200), EGL-406M (210004039700).
Hearth and Source Material Handling
- Inspect hearth for cracks or run-out at each vent — replace cracked hearths immediately
- For reactive materials (Ti, Al, Cu): use compatible liner hearths to prevent alloying with copper hearth body
- Do not overfill crucible — melt pool must remain below hearth rim
- Handle hearths only with clean gloves — contamination causes arc events
HPS Power Generator Maintenance
- Water cooling: verify coolant flow rate annually; flush if scale suspected; never operate without cooling water
- HV cable and connectors: inspect annually for insulation damage, corona tracking, or corrosion
- Arc event log: monitor cumulative arc count — high arc rate indicates gun needs conditioning or vacuum is insufficient
- Do not operate HPS with cabinet panels removed — HV present on internal components even when HV enable is off
Fault Diagnosis
| Symptom | Probable Cause | Action |
|---|---|---|
| No electron emission | Filament broken or disconnected; loose gun body connector | Inspect filament; replace if broken; check gun body connector |
| High arc rate | Source material contamination or moisture; insufficient vacuum | Condition gun at low power; dry source material; verify chamber vacuum level |
| Low deposition rate at nominal power | Beam not focused on hearth; sweep misaligned; source material level low | Check sweep calibration and focus coil current; check source material level |
| HV trips on pressure interlock | Chamber vacuum insufficient | Verify working vacuum achieved before applying HV; check pumps and gauges |
| Uneven film thickness across substrate | Uneven beam sweep amplitude; incorrect source-to-substrate geometry | Recalibrate sweep amplitude and offset; verify gun position in chamber |
| Filament runs hot at low emission | Cathode contaminated or poisoned by process vapour | Condition at low emission; replace filament if performance not recovered |
| HPS controller overcurrent alarm | Arc in gun or HV cable; insulation breakdown | Inspect HV cable and gun interior; clean all insulating components |
Training
Safety briefing, operator training, and maintenance training are available for EB gun systems. Safety briefing covers HV lockout/tagout procedures, X-ray radiation shielding requirements, and interlock verification. Operator training covers startup sequence, beam conditioning, sweep calibration, source material handling, and multi-crucible indexing. Maintenance training covers filament replacement, hearth inspection and replacement, and HPS generator PM procedure. Contact mail@ulvacheliot.com — provide: gun model, HPS model, site location, number of attendees.
Service Enquiry
Email mail@ulvacheliot.com — provide: gun model (EGK/EGL/EGN/EGO series), HPS generator model, serial numbers, fault description including HV setting, emission current, arc count, and alarm codes. Photos of hearth condition and any visible damage are helpful. Filaments, hearths, and crucibles are available — specify gun model and hearth crucible configuration when ordering.