Date of Award

Spring 5-10-2019

Level of Access

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

Advisor

Nuri Emanetoglu

Second Committee Member

Robert Lad

Third Committee Member

David Frankel

Additional Committee Members

Robert Meulenberg

James McClymer

Abstract

Low temperature (LT) growth of strongly textured AlN by molecular beam epitaxy (MBE) has not been extensively investigated. The low mobility of Al adatoms provides a challenge for growth of AlN at low temperatures (<600 >°C). Consequently, AlN growth by MBE is typically at temperatures >700 °C. Growth at these temperatures can limit the selection of substrates and materials to grow with the AlN. Highly oriented, LT AlN thin films (<50 >nm) were grown on c-­‐plane sapphire, using an interrupted growth procedure. Films were grown by periodically interrupting the Al flux with a nitridation. This two-­‐step cycle was repeated until the AlN film reached the desired thickness. For comparison, two groups of AlN thin films were grown using an uninterrupted growth. One group was grown using an Al/N ratio >1, and the other grown with an Al/N<1 were multiply oriented, with poor surface morphology. Comparison films grown with an Al/N<1, strongly textured films resulted from depositing 5-­‐6 monolayers of AlN, and interrupting each growth with a 2–3 minute nitridation. The N* of a 600 W plasma produced a smooth surface. Using a 300W plasma increased surface roughness.

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