Doped or Quantum-Dot Layers as In Situ Etch-Stop Indicators for III/V Semiconductor Reactive Ion Etching (RIE) Using Reflectance Anisotropy Spectroscopy (RAS)
| Autor: | Emerson Oliveira, Henning Fouckhardt, Christoph Doering, Johannes Strassner, Johannes M. Richter, Guilherme Sombrio |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
etch-depth monitoring quantum dots 02 engineering and technology Substrate (electronics) Epitaxy 01 natural sciences Article Lattice constant reactive ion etching (RIE) 0103 physical sciences TJ1-1570 Mechanical engineering and machinery Electrical and Electronic Engineering Reactive-ion etching Spectroscopy 010302 applied physics business.industry Mechanical Engineering Doping fungi technology industry and agriculture 021001 nanoscience & nanotechnology Semiconductor etch-stop indicator layers Control and Systems Engineering Quantum dot III/V semiconductors Optoelectronics 0210 nano-technology business reflectance anisotropy spectroscopy (RAS) |
| Zdroj: | Micromachines Volume 12 Issue 5 Micromachines, Vol 12, Iss 502, p 502 (2021) |
| ISSN: | 2072-666X |
| DOI: | 10.3390/mi12050502 |
| Popis: | Reflectance anisotropy spectroscopy (RAS), which was originally invented to monitor epitaxial growth, can—as we have previously shown—also be used to monitor the reactive ion etching of III/V semiconductor samples in situ and in real time, as long as the etching rate is not too high and the abrasion at the etch front is not totally chaotic. Moreover, we have proven that— using RAS equipment and optical Fabry-Perot oscillations due to the ever-shrinking thickness of the uppermost etched layer—the in situ etch-depth resolution can be as good as +/-0.8 nm, employing a Vernier-scale type measurement and evaluation procedure. Nominally, this amounts to +/-1.3 lattice constants in our exemplary material system, AlGaAsSb, on a GaAs or GaSb substrate. In this contribution, we show that resolutions of about +/-5.6 nm can be reliably achieved without a Vernier scale protocol by employing thin doped layers or sharp interfaces between differently doped layers or quantum-dot (QD) layers as etch-stop indicators. These indicator layers can either be added to the device layer design on purpose or be part of it incidentally due to the functionality of the device. For typical etch rates in the range of 0.7 to 1.3 nm/s (that is, about 40 to 80 nm/min), the RAS spectrum will show a distinct change even for very thin indicator layers, which allows for the precise termination of the etch run. |
| Databáze: | OpenAIRE |
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