Opto Diode builds two silicon photodiode families for the soft x-ray and extreme-ultraviolet (EUV) range, and both detect down into the same difficult part of the spectrum where conventional windowed detectors fall short. The difference is in how each is optimized: AXUV is engineered for absolute, calibration-grade response across an exceptionally broad band, while SXUV is hardened to survive the high-intensity EUV environments that would degrade an ordinary diode. Choosing the wrong family means either leaving sensitivity on the table or watching responsivity drift mid-program — so the selection deserves a deliberate look.
AXUV vs SXUV at a Glance
| Parameter | AXUV | SXUV |
|---|---|---|
| Wavelength / spectral range | 0.0124 nm to 190 nm; detects energy from 100 eV to 50 keV | 1 nm to 200 nm (individual models labeled 1 nm–190 nm) |
| Quantum efficiency | 100% internal quantum efficiency (UV to visible spectrum) | Broad spectral responsivity (specific QE values not published on the page) |
| Window / construction | Windowless for enhanced response below 200 nm | Detector construction details not published on the page |
| Radiation hardness | Not specified as a primary attribute | High radiation hardness; low-noise performance |
| Representative active areas | 3, 10, 20, 23, 36.5, 63, 100, 331, 576.5 mm² | 1.25, 5, 20, 100, 331 mm² |
| Primary applications | Electron detection, synchrotron radiation monitoring, electron reticle inspection | EUV lithography, x-ray spectroscopy, synchrotron radiation monitoring |
All specifications above are drawn directly from the Opto Diode AXUV and SXUV product-category pages.
Choose AXUV if…
- You need 100% internal quantum efficiency for absolute, calibration-grade radiometry rather than relative measurements.
- Your work spans an extremely broad band — 0.0124 nm to 190 nm, covering energies from 100 eV up to 50 keV — and you want a single detector technology across photons, electrons, and x-rays.
- A windowless front end is acceptable (and desirable), since it delivers enhanced response below 200 nm without window-absorption losses.
- Your application is electron detection, synchrotron radiation monitoring, or electron reticle inspection.
- You need a wide menu of active areas, from a compact 3 mm² up to a large 576.5 mm², to match beam size or solid-angle requirements.
Choose SXUV if…
- Your detector will see high-intensity EUV flux, where high radiation hardness is essential to maintain stable responsivity over the life of the program.
- You are working in EUV lithography — the headline application for this family — and need a diode that holds up under repeated, intense EUV exposure.
- You want low-noise performance combined with broad spectral responsivity across roughly 1 nm to 200 nm.
- Your application is x-ray spectroscopy or synchrotron radiation monitoring in an environment that would degrade a non-hardened diode.
Representative Models
AXUV detectors (browse the full AXUV line):
- AXUV20HS1 (20 mm²) and AXUV20A (23 mm²)
- AXUV63HS1, AXUV63HS1-CH (63 mm² class)
- AXUV100G, AXUV100TF030, AXUV100TF400 (100 mm² class)
- AXUV300C (331 mm²) and AXUV576C (576.5 mm²) for large-area needs
- AXUV16ELG, AXUV20ELG, and AXUVPS7 for specialized configurations
SXUV detectors (browse the full SXUV line):
- SXUVPS4, SXUVPS4C (1.25 mm² class)
- SXUV5 (5 mm²)
- SXUV20HS1, SXUV20C (20 mm² class)
- SXUV100, SXUV100TF135 (100 mm² class)
- SXUV300C (331 mm²) for large-area EUV monitoring
Model availability, active-area options, and thin-film coatings vary; confirm the exact configuration against the current product pages before specifying.
The Bottom Line
If your priority is absolute quantum efficiency over the widest possible band — for synchrotron, electron, and x-ray work — AXUV is the natural starting point. If your priority is surviving high-intensity EUV with stable responsivity — the defining requirement of EUV lithography — SXUV is built for that duty. Both families are designed and built by Opto Diode — a US-based ITW company in Camarillo, California — with the engineering support to match a detector to your application.
Not sure which family — or which active area and coating — fits your beamline or tool? Contact Opto Diode for a quote and application support and our team will help you match the detector to your spectral range, geometry, and radiation environment.
Frequently Asked Questions
Which family has higher quantum efficiency?
The AXUV family is specified with 100% internal quantum efficiency from the UV into the visible spectrum, making it the choice when absolute, calibration-grade response matters. The SXUV pages describe broad spectral responsivity but do not publish specific quantum-efficiency figures.
Which photodiode is right for EUV lithography?
SXUV. EUV lithography is the lead application for the SXUV family, which pairs high radiation hardness with low-noise performance to keep responsivity stable under intense EUV exposure.
Which family is more radiation-hard?
SXUV is the radiation-hardened family, explicitly characterized by high radiation hardness for demanding EUV and x-ray environments. AXUV is optimized instead for windowless broadband response and 100% internal quantum efficiency.
Can Opto Diode customize these detectors?
Both families ship in a range of active areas — from 1.25 mm² up to 576.5 mm² across the two lines — along with various model configurations and thin-film options. For specific active-area, coating, or packaging requirements, reach out for a quote to discuss your application.