III-Nitride based

Get control of your III-Nitride process from Epi to Etch.

Applications Metrology solutions Related products

III-nitrides are composed of an element of group III (Al, Ga, In, …) and nitrogen. These compounds are characterized by their relatively large electronic band gap. The main applications of these compounds are accordingly, for example, high voltage transistors for power applications such as electric vehicle power controls or DC/AC inverters for wind or solar applications or UV-LEDs. Depending on the particular layer stack and the compounds deposited different substrates are used, for example (patterned) sapphire, SiC-4H or silicon (see also next section).

  • Wafer temperature with precision better than ±1K in a range of 600°C to 1400°C Capability for True Temperature measurements to up to 1500°C

  • High accuracy in-situ growth rate (film thickness) measurement with XRD accuracy by 405/633/950 nm low-noise 3-wavelength reflectance

  • 24/7 performance with automated data analysis and integrated interfaces to the MES/SPC systems of our customers

  • Additional UV wavelength for increased sensitivity of UV emitting layers

  • Increased sensitivity to surface morphology for UV wavelengths

Name Size
EpiX Data Sheet 3.32 MB
Newsletter April 2020 - AlInN composition control for III-Nitride VCSELs 524.93 KB
Talk - 280 nm reflectometry helpful tool for in-situ control of AlN-based MOVPE growth 876.51 KB
Talk - How to enhance epitaxy process performance by in-situ data 3.4 MB
Talk - Metrology for UV-LEDs, VCSEL and Power electronics 3.26 MB
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Metrology solutions

Growth of AlN/AlGaN(60%Al) on a Sapphire/AlN template in Aixtron CCS 6x2 reactor: black – 280 nm reflectance; blue – 405 nm reflectance; green –  high-resolution wafer bow; red – true temperature. This study is supported by Advanced UV for Life funding (grant number 03ZZ0105C, BMBF).

Reflectance based metrology solution

For UV-LEDs, precise monitoring of both AlGaN growth rate and surface morphology during UV-C LED epitaxy is needed. Therefore, LayTec offers additional 280 nm and 365 nm reflectance channels as an addition to its well-established EpiCurve® TT product family. Besides these additional features, also the established EpiCurve® TT features (ECP, waferbow monitoring etc.). The figure shows the results measured in-situ during the growth of an AlGaN layer: The Fabry-Perot oscillations of the final AlGaN layer are damping out because the band edge of the material shifts towards longer wavelength at the growth temperature. The small reflectance reduction at 12000 s indicates a small roughening of the AlGaN surface.

The green line also delivers the high-resolution wafer bow data: at ~1000 s the strain changes from compressive towards tensile during AlGaN growth with accuracy levels comparable to ex-situ XRD methods.

In the field of power devices, the initial AlN growth on SiC-6H is performed at very high wafer temperature (measured by Pyro 400 at ±0.5 K accuracy) and with a sophisticated three-temperature process. This ensures significant defect reduction for the subsequent HEMT growth. Despite the varying wafer temperature in this AlN buffer growth process, the latest real-time analysis function library of LayTec's EpiNet® software allows our tools to reach ±0.5 nm accuracy in real-time AlN film thickness measurement. This has been achieved by tightly correlating the absolute SiC-4H wafer temperature with high accuracy SiC-4H and AlN nk optical data and implementing new analysis algorithms that separate reflectance changes caused by temperature ramping from the AlN growth effects.

Contact

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