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Surface Morphology and Electric Property of the AlGaN/AlN/GaN Multilayers with Varying the AlN Thickness

Published online by Cambridge University Press:  10 October 2013

Shih-Chun Huang ,
Wen-Ray Chen ,
Jia-Ching Lin ,
Kuo-Jen Chang ,
Wen-Jen Lin  and
Li-Chun Wang
Shih-Chun Huang
Affiliation:
Graduate Institute of Electro-Optical and Materials Science, National Formosa University, Huwei 632, Taiwan, R.O.C.
Wen-Ray Chen*
Affiliation:
Department of Electronic Engineering, National Formosa University, Yunlin 632, Taiwan, Phone:+886-5-6315648, E-mail:chenwr@nfu.edu.tw
Jia-Ching Lin
Affiliation:
Materials and Electro-Optics Research Division, Chung Shan Institute of Science and Technology, Taoyuan 325, Taiwan, R.O.C.
Kuo-Jen Chang
Affiliation:
Materials and Electro-Optics Research Division, Chung Shan Institute of Science and Technology, Taoyuan 325, Taiwan, R.O.C.
Wen-Jen Lin
Affiliation:
Materials and Electro-Optics Research Division, Chung Shan Institute of Science and Technology, Taoyuan 325, Taiwan, R.O.C.
Li-Chun Wang
Affiliation:
Chemical System Research Division, Chung Shan Institute of Science and Technology, Taoyuan 325, Taiwan, R.O.C.
*
*Email: chenwr@nfu.edu.tw
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Abstract

The surface morphologies of AlGaN/AlN/GaN HEMT structures were examined by using the atomic force microscopy (AFM).These HEMT structures have been grown by metalorganic chemical vapor deposition (MOCVD) onto the sapphire (0001) substrates where the thicknesses of AlN interlayers were varied from 0 to 5 nm. After the growth of GaN buffer layer, the AlN intermediate and AlGaN top layers were subsequently deposited at 1130°C in an trimethylaluminum (TMAl) and ammonia (NH3) atmosphere. The surface of AlGaN layers shows the thick- and fine-thread patterns.

It was found that the root-mean-square (RMS) roughness of the samples with 0, 0.5, 2.5 and 5nm AlN interlayer thickness are 0.503, 0.534, 0.534 and 0.601nm, respectively. Although the cracks and rougher surfaces show that the qualities of AlGaN barrier layers have slightly degraded in the samples with thicker AlN layer. These phenomena could be attributed to the lattice mismatch and the growth temperature. In addition, the room-temperature two-dimensional electron gas (2DEG) mobility and density analysis were performed on the AlGaN surfaces and the measured results were discussed in detail.

Keywords

electrical propertiesstructuralmorphology
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1515: Symposium II – Atomic Structure and Chemistry of Domain Interfaces and Grain Boundaries , 2013 , mrsf12-1515-ii13-11
Copyright
Copyright © Materials Research Society 2013 

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References

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