Dataset for "AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy"

This dataset contains scanning electron microscopy (SEM) images of nano-pillar-patterned sapphire created via Displacement Talbot Lithography and Inductively coupled plasma dry etching.

Electrical engineering
Materials sciences

Cite this dataset as:
Coulon, P., 2019. Dataset for "AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy". Bath: University of Bath Research Data Archive. Available from:


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Creative Commons: Attribution 4.0

image/tiff (175kB)
Creative Commons: Attribution 4.0

image/tiff (429kB)
Creative Commons: Attribution 4.0



Philip Shields
Project Leader
University of Bath

University of Bath
Rights Holder


Data collection method:

Secondary electron images were captured using a Hitachi S-4300 scanning electron microscope (SEM). An accelerating voltage of 5 kV was used to collect the images

Technical details and requirements:

DTL patternings have been performed on 2-inch sapphire wafers. A stack of two layers was spin-coated at 3000 rpm to obtain a ~ 270 nm bottom antireflective coating (BARC) (Wide 30W – Brewer Science) layer thickness, followed by either a layer of high-contrast positive resist (Dow® Ultra-i 123 diluted with Dow® EC11 solvent). A bake at 150°C of the BARC enables a wet-developable process and thus to create an undercut profile. DTL (PhableR 100, Eulitha) was then used to expose the resist with a coherent 375 nm light source with an energy density of 1 (Fig. 1a). A 1 μm pitch with 550 nm opening mask was employed which result in a Talbot length of 3.80 μm. A Gaussian velocity integration was applied and 8 Talbot lengths travel distance has been chosen to assure a homogeneous integration on several Talbot motifs. After a certain exposure time (which defines the exposure dose), the sample was baked for 1 min 30 sec at 120°C on a hot plate. The wafer was developed in MF-CD-26 for 180 to 240 sec (depending on the dose employed). The undercut profile created in the BARC after exposure and development was employed as a lift-off layer. 200 nm Ni layers were deposited via e-beam evaporation to produce metal masks in the circular opening at the surface of the wafer. Subsequent lift-off was achieved by soaking the wafer in MF-CD-26 developer. The wafers were cleaned in a 2 min reactive-ion etching (RIE) oxygen plasma to remove any BARC residue. Then, an ICP dry etch system was used to create nano-pillars in sapphire substrates. The experiments were performed with a Cl2/BCl3/Ar chemistry of 5/50/5 sccm, a temperature of 5°C, a pressure of 8 mTorr, 100 W RF power and 600 W ICP source power. Finally, the masks were etched away in aqua-regia solution (HCl:HNO3, 3:1).


Engineering and Physical Sciences Research Council (EPSRC)

Manufacturing of Nano-Engineered III-N Semiconductors

Publication details

Publication date: 13 November 2019
by: University of Bath

Version: 1


URL for this record:

Related articles

Walde, S., Hagedorn, S., Coulon, P.-M., Mogilatenko, A., Netzel, C., Weinrich, J., Susilo, N., Ziffer, E., Matiwe, L., Hartmann, C., Kusch, G., Alasmari, A., Naresh-Kumar, G., Trager-Cowan, C., Wernicke, T., Straubinger, T., Bickermann, M., Martin, R.W., Shields, P.A., Kneissl, M. and Weyers, M., 2020. AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy. Journal of Crystal Growth, 531, p.125343. Available from:

Contact information

Please contact the Research Data Service in the first instance for all matters concerning this item.

Contact person: Pierre-Marie Coulon


Faculty of Engineering & Design
Electronic & Electrical Engineering

Research Centres & Institutes
Centre for Nanoscience and Nanotechnology