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Measurements of strain in AlGaN/GaN HEMT structures grown by plasma assisted molecular beam epitaxy |
Jolanta Borysiuk 1, Kamil Sobczak 1, Aleksandra Wierzbicka 1, Kamil Klosek 1, Marta Sobanska 1, Zbigniew R. Zytkiewicz 1, Boleslaw L. Lucznik 2 |
1. Institute of Physics, Polish Academy of Sciences, Warsaw 02-668, Poland |
Abstract |
The AlGaN/GaN high electron mobility transistor (HEMT) structures were grown on the (0001) HVPE bulk GaN substrates using plasma-assisted molecular-beam epitaxy (PAMBE). The AlGaN layers of content of 12% or 20% were grown to nominal 20nm thickness and the 3nm thick GaN cap was added. High-resolution X-ray diffraction (HRXRD) measurements were used to determine crystallographic quality of HEMT structures. Built-in strain was obtained from peak intensity analysis. An effective lattice constant was derived from the shifts of the peaks positions. These X-ray data were compared to local measurements performed by transmission electron microscopy (TEM) – Fig.1. Tetragonal distortion was used for lattice strain in the interface regions. Structure geometry was also obtained from TEM images. Overall quality of the structures and their performance was assessed.![]() ![]() Figure 2. XRD map of the (11 4) reflection. Acknowledgements This work was partially supported by the European Union within European Regional Development Found, through grant Innovative Economy POIG.01.01.02-00-008/08 NanoBiom. One of the authors (JB) wishes to thank the National Science Centre (Poland) support by grant DEC-2011/03/B/ST5/02698. |
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Presentation: Poster at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, General Session 5, by Jolanta Borysiuk Submitted: 2013-04-15 19:04 Revised: 2013-07-26 09:03 |