Mosaic Structure Characterization of the AlInN Layer Grown on Sapphire Substrate

Engin Arslan,Huseyin Çakmak,Mustafa K Öztürk,Ekmel Ozbay,Pakize Demirel

doi:10.1155/2014/980639

Engin Arslan, Huseyin Çakmak + Show 3 more

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https://doi.org/10.1155/2014/980639

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Abstract

The 150 nm thick, (0001) orientated wurtzite-phase Al1−xInxN epitaxial layers were grown by metal organic chemical vapor deposition on GaN (2.3 µm) template/(0001) sapphire substrate. The indium (x) concentration of the Al1−xInxN epitaxial layers was changed as 0.04, 0.18, 0.20, 0.47, and 0.48. The Indium content (x), lattice parameters, and strain values in the AlInN layers were calculated from the reciprocal lattice mapping around symmetric (0002) and asymmetric (10–15) reflection of the AlInN and GaN layers. The mosaic structure characteristics of the AlInN layers, such as lateral and vertical coherence lengths, tilt and twist angle, heterogeneous strain, and dislocation densities (edge and screw type dislocations) of the AlInN epilayers, were investigated by using high-resolution X-ray diffraction measurements and with a combination of Williamson-Hall plot and the fitting of twist angles.

Highlights

Because of the large band gap, large breakdown field, and strong spontaneous and piezoelectric polarization field’s properties of the III-nitride materials systems, they have been used in optoelectronic devices, such as light emitting diodes, blue/ultraviolet lasers, metal-semiconductor field effect transistors, modulation-doped field effect transistors, photodetectors, and high temperature/high power electronic devices [1,2,3]
We present investigations of the mosaic properties of Al1−xInxN grown in the composition range 0.04, 0.18, 0.20, 0.47, and 0.48 on GaN/sapphire structures by metal organic chemical vapor phase deposition (MOCVD)
The surface morphology of the AlInN epilayers grown on GaN template layers is characterized by atomic force microscopy (AFM)

Summary

Introduction

Because of the large band gap, large breakdown field, and strong spontaneous and piezoelectric polarization field’s properties of the III-nitride materials systems, they have been used in optoelectronic devices, such as light emitting diodes, blue/ultraviolet lasers, metal-semiconductor field effect transistors, modulation-doped field effect transistors, photodetectors, and high temperature/high power electronic devices [1,2,3]. Many studies have been performed to improve the structural quality of GaN based alloys and the performance of devices, such as increasing the Al composition of an AlGaN barrier, using a thin AlN spacer layer at the AlGaN/GaN interface, and replacing the GaN by InGaN as the channel and AlGaN by AlInN layer as a barrier [12, 13]. Among these studies, it is possible to grow a lattice-matched AlInN layer on GaN layer for an In concentration of ∼18% [12,13,14]. AlInN alloys can possibly be used for light emitters and detectors operating in extremely wide spectral regions covering from deep infrared to UV since the alloys band-gap energy (Eg) can range from 0.7 eV (InN) to 6.2 eV (AlN) [1,2,3]

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