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Alloying during local droplet etching of AlGaAs surfaces with aluminium
- Source :
- Journal of Applied Physics. 125:025306
- Publication Year :
- 2019
- Publisher :
- AIP Publishing, 2019.
-
Abstract
- Local droplet etching (LDE) drills self-assembled nanoholes into AlGaAs surfaces and represents a powerful technique for the fabrication of versatile quantum structures like quantum dots, rings, and molecules. Usually, LDE is performed at temperatures T = 600 − 680 ° C if Al is used as the etching material. Now, atomic force microscopy establishes that Al-LDE drills nanoholes also at very low temperatures down to T = 360 ° C which is 300 ° C below the melting point of bulk Al. Several possible etching mechanisms like a melting-point depression, solid-state etching, and alloying are discussed. Selective wet-chemical etching experiments using HF indicate significant alloying with Ga from the substrate, and thus the formation of Al-Ga droplets for etching. The upper limit of x ≤ 50 % for the Al content inside the Al-Ga droplets is indicated by the selectivity of the HF acid. This value is in agreement with an estimation of x = 0.42, which is based on the measured droplet and hole volumes. A comparison with the Al-Ga phase diagram indicates that a completely liquid phase of the droplets is essential for etching.
- Subjects :
- 010302 applied physics
Fabrication
Materials science
Analytical chemistry
General Physics and Astronomy
chemistry.chemical_element
02 engineering and technology
Substrate (electronics)
021001 nanoscience & nanotechnology
01 natural sciences
chemistry
Etching (microfabrication)
Quantum dot
Aluminium
0103 physical sciences
Melting point
Molecule
0210 nano-technology
Phase diagram
Subjects
Details
- ISSN :
- 10897550 and 00218979
- Volume :
- 125
- Database :
- OpenAIRE
- Journal :
- Journal of Applied Physics
- Accession number :
- edsair.doi...........ce17fa9b3bf8e7b12c7d3a2f390b45c8