Dislocation reduction in high Al-content AlGaN films for deep ultraviolet light emitting diodes

被引：13

作者：

Ahmad, Iftikhar ^{[1
]}

Krishnan, Balakrishnan ^{[2
]}

Zhang, Bin ^{[2
]}

Fareed, Qhalid ^{[1
,2
]}

Lachab, Mohamed ^{[2
]}

Dion, Joseph ^{[2
]}

Khan, Asif ^{[2
]}

机构：

[1] Nitek Inc, Irmo, SC USA

[2] Univ S Carolina, Dept Elect Engn, Columbia, SC 29208 USA

来源：

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE | 2011年 / 208卷 / 07期

基金：

美国国家科学基金会;

关键词：

AlGaN; low dislocation density AlGaN; photonics; UV-LED;

D O I：

10.1002/pssa.201001104

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We report a new approach for growing thicker (>2 mu m) low-defect AlGaN layers over sapphire using pulsed MOCVD procedure. These high content AlGaN layers serve as templates for subsequent n-AlGaN growth for deep ultraviolet light emitting diodes (DUV LEDs). During the growth of the Al(x)Ga(1-x)N layer, the pulsed-growth conditions were cyclically adjusted to reduce the dislocations. This leads to AlGaN templates with an RMS roughness of 9.6 angstrom and (102) off-axis X-ray line-width 550 arcsec. The transmission electron microscope (TEM) analysis shows 4 x 10(7)cm(-2) edge type and 2 x 10(6) cm(-2) screw type of threading dislocation densities at best regions. On the average dislocation density in these films is 4 x 10(8) cm(-2). A light emitting diode (LED) structure emitting at 280 nm was deposited on these templates. A comparative study showed the EL emission for LEDs on the new low-defect templates to be more than 1.6 times stronger than our conventional DUV LED structures. In this paper the details of our growth procedure, the epi-structure X-ray, atomic force microscopy (AFM), TEM, and other characterizations will be presented. A comparative study of DUV LED structures over conventional and improved templates of this work will be discussed. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

引用

页码：1501 / 1503

页数：3

共 4 条

[1]

Adivarahan V., 2008, INT S SEM LIGHT EM D

[2] 231-261 nm AlGaN deep-ultraviolet light-emitting diodes fabricated on AlN multilayer buffers grown by ammonia pulse-flow method on sapphire [J].