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R&D and process control of Novel LED devices with the CAMECA IMS 7f
Optimized doping (Mg, Si, Zn,...) and reduced impurity incorporation (H, C, O, metals) are essential for high efficiency LED devices. Using dynamic SIMS, depth profiles can be recorded up to several microns within minutes, with detection limits from the ppm down to the ppb range depending on the species to be analyzed. Dynamic SIMS also offers high depth resolution, which has been widely used for ultra shallow implant technology. Therefore, the CAMECA SIMS instruments are extremely useful in investigating the composition and characterizing the elemental distribution of dopants and impurities on different layers, making them your best choice for R&D and process control of novel LED devices.
Doping and structure compostion monitoring
Based on a magnetic sector mass spectrometer, the IMS 7f achieves benchmark performance in terms of sensitivity, depth resolution and mass resolution... SIMS depth profiling measurements are typically performed using the following experimental conditions:
- MCs+ mode for both matrix species and P-type dopants (Mg, Zn).
- Cs+ primary ions and negative secondary ion detection for N-type dopants. In particular, the 28Si signal is analyzed using high mass resolution to eliminate the interferences between 28Si and 27Al1H or 14N2 in GaN based LEDs.
These conditions provide the required detection limits for both P- and N-type dopants. Moreover, they offer optimized throughput and ease of use, as only one primary ion source is used for analyzing all species.
Impurity control and failure analysis
In LED compounds, undesirable contamination of H, C and O into defects of GaN crystalline structure affect the electrical properties and shift the intended emission wavelength.
The detection limits of dynamic SIMS surpass the capabilities of competing techniques, therefore, SIMS is a particularly attractive technique for the analysis of light elements. Typical detection limits with the CAMECA dynamic SIMS instruments are ~5E17 at/cm3 for Hydrogen, ~1E17at/cm3 for Carbon, ~5E16 at/cm3 for Oxygen.
For further details, you may request the SIMS for LEDs application note.