کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8151426 | 1524441 | 2014 | 31 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Low dislocation density AlGaN epilayers by epitaxial overgrowth of patterned templates
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
فیزیک ماده چگال
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![عکس صفحه اول مقاله: Low dislocation density AlGaN epilayers by epitaxial overgrowth of patterned templates Low dislocation density AlGaN epilayers by epitaxial overgrowth of patterned templates](/preview/png/8151426.png)
چکیده انگلیسی
We present an epitaxial overgrowth process for reducing threading dislocations in AlxGa1âxN over the entire compositional range. This process avoids the use of UV-absorbing GaN layers and results in a spatially uniform defect reduction which eliminates the need for precise alignment of devices to low-defect areas of the wafer. Using the described overgrowth process, we demonstrate Al0.3Ga0.7N and Al0.6Ga0.4N epilayers with a dislocation density of 2Ã108 cmâ2 and 5Ã108 cmâ2 respectively, rendering them suitable as templates for deep-UV bottom-emitting LEDs and laser diodes. The process involves patterning of submicron-wide-stripes, less than 1 μm in height, into an AlGaN/AlN/sapphire template and subsequent regrowth of a 5-10 μm thick AlGaN epilayer. The sub-micron width of the mesa allows for bending of threading dislocations that would continue to thread vertically through wider mesas. Utilizing 1.3 mm-thick sapphire substrates (3à thicker than commonly used), epilayer cracking from regrowth is eliminated and wafer bow over a 2-in. diameter substrate is reduced to less than 15 μm. We observed a 7à increase in photoluminescence intensity from GaN-AlGaN multi-quantum well structures emitting at 340 nm and a 15à increase in electroluminescence from laser diode heterostructures when grown on patterned Al0.3Ga0.7N templates.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Crystal Growth - Volume 388, 15 February 2014, Pages 76-82
Journal: Journal of Crystal Growth - Volume 388, 15 February 2014, Pages 76-82
نویسندگان
A.A. Allerman, M.H. Crawford, S.R. Lee, B.G. Clark,