Article
Nondestructive Analysis of Al2O3/SiOx/Si Passivation Layers for Photovoltaics Using Angle-Resolved HAXPES Techniques
Surface Analysis Spotlight: XPS
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Revealing Hidden Interface Changes in Si/SiOₓ/Al₂O₃ Stacks with AR-HAXPES
The performance of advanced semiconductor devices depends heavily on the quality of buried interfaces. In Si/SiOₓ/Al₂O₃ structures, the thin interfacial SiOₓ layer plays a critical role in controlling leakage current, dark current, and threshold voltage stability. However, studying this layer becomes increasingly challenging when covered by thick Al₂O₃ dielectric films.
In our study, we used angle-resolved XPS (AR-XPS) and angle-resolved hard X-ray photoelectron spectroscopy (AR-HAXPES) to investigate the impact of post-annealing treatments on Si/SiOₓ/Al₂O₃ stacks. Both techniques showed that the interfacial SiOₓ layer grows thicker as annealing temperature increases. Thanks to its greater probing depth, AR-HAXPES provides a more accurate and non-destructive method for evaluating buried interface layers without sputtering-related damage.
Additionally, in situ heating HAXPES enabled real-time observation of chemical-state evolution during annealing, capturing transient sub-oxide states that may disappear during cooling or air exposure. These insights provide valuable guidance for optimizing annealing conditions, interface passivation, and overall device reliability.
Key Highlights
- SiOₓ thickness increases with annealing temperature
- AR-HAXPES accurately probes buried interfaces beneath thick (>15 nm) Al₂O₃ layers
- Non-destructive analysis eliminates sputter-induced chemical modifications
- In situ heating HAXPES captures real-time interface chemical evolution
- Transient sub-oxide states can be observed before they disappear during cooling
- Results support improved annealing optimization, interface passivation, and electrical performance in semiconductor devices
Takeaway
AR-HAXPES and in situ heating HAXPES provide powerful tools for understanding and optimizing buried interfaces in next-generation semiconductor devices, delivering deeper insights into thermal processing effects that directly influence device performance and reliability.
To learn more about angle-dependent XPS, please join us for Dr. Hsun-Yun Chang’s presentation “Nondestructive Analysis of Al2O3/SiOx/Si Passivation Layers for Photovoltaics Using Angle-Resolved HAXPES Techniques” at ECASIA 26 on Tuesday, Sept 15 at 11:30 AM.
