Analysis of composition fluctuations on an atomic scale in Al0.25Ga0.75N by high-resolution transmission electron microscopy

被引：18

作者：

Neubauer, B ^{[1
]}

Rosenauer, A

Gerthsen, D

Ambacher, O

Stutzmann, M

机构：

[1] Univ Karlsruhe, Lab Elektronenmikroskopie, D-72128 Karlsruhe, Germany

[2] Tech Univ Munchen, Walter Schottky Inst, D-85748 Garching, Germany

来源：

APPLIED PHYSICS LETTERS | 1998年 / 73卷 / 07期

关键词：

D O I：

10.1063/1.122041

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Composition fluctuations in the Al0.25Ga0.75N layer of an AlGaN/GaN transistor structure grown by plasma induced molecular beam epitaxy on Al2O3(0001) at a growth temperature of 870 degrees C were studied by digital analysis of lattice images (DALI) of high-resolution transmission electron microscopy (HRTEM) cross-section images. DALI exploits the linear dependence of the lattice parameters on the Al content by applying Vegard's law. Detecting the distances between intensity maxima positions in the micrograph which can be considered as a fingerprint of the local lattice parameters quantitatively derives composition profiles on an atomic scale. In the HRTEM cross-section image different areas were observed in the Al0.25Ga0.75N layer with either homogeneous or "striped" contrast, Tn the striped areas the analyses indicate a strong periodic decomposition with a period of 1 nm consisting of 1 ML Al0.8Ga0.2N and about 3 ML Al0.07Ga(0.93)N. The regions with homogeneous contrast do not exhibit significant composition fluctuations. (C) 1998 American Institute of Physics.

引用

页码：930 / 932

页数：3

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