Strain and composition distributions in wurtzite InGaN/GaN layers extracted from x-ray reciprocal space mapping

被引:221
作者
Pereira, S [1 ]
Correia, MR
Pereira, E
O'Donnell, KP
Alves, E
Sequeira, AD
Franco, N
Watson, IM
Deatcher, CJ
机构
[1] Univ Aveiro, Dept Fis, P-3810193 Aveiro, Portugal
[2] Univ Strathclyde, Dept Phys, Glasgow G4 0NG, Lanark, Scotland
[3] ITN, Dept Fis, EN 10, P-2686953 Sacavem, Portugal
[4] Univ Strathclyde, Inst Photon, Glasgow, Lanark, Scotland
关键词
D O I
10.1063/1.1481786
中图分类号
O59 [应用物理学];
学科分类号
摘要
Strain and composition distributions within wurtzite InGaN/GaN layers are investigated by high-resolution reciprocal space mapping (RSM). We illustrate the potential of RSM to detect composition and strain gradients independently. This information is extracted from the elongation of broadened reciprocal lattice points (RLP) in asymmetric x-ray reflections. Three InxGa1-xN/GaN (nominal x=0.25) samples with layer thickness of 60, 120, and 240 nm, were grown in a commercial metal-organic chemical vapor deposition reactor. The RSMs around the (105) reflection show that the strain profile is nonuniform over depth in InGaN. The directions of "pure" strain relaxation in the reciprocal space, for a given In content (isocomposition lines), are calculated based on elastic theory. Comparison between these directions and measured distributions of the RLP shows that the relaxation process does not follow a specific isocomposition line. The In mole fraction (x) increases as the films relax. At the start of growth all the films have xsimilar to0.2 and are coherent to GaN. As they relax, x progressively increases towards the nominal value (0.25). Compositional gradients along the growth direction extracted from the RSM analysis are confirmed by complementary Rutherford backscattering measurements. (C) 2002 American Institute of Physics.
引用
收藏
页码:3913 / 3915
页数:3
相关论文
共 19 条
[1]  
Chierchia R, 2001, PHYS STATUS SOLIDI B, V228, P403, DOI 10.1002/1521-3951(200111)228:2<403::AID-PSSB403>3.0.CO
[2]  
2-5
[3]   RELAXATION PROCESS OF THE THERMAL STRAIN IN THE GAN/ALPHA-AL2O3 HETEROSTRUCTURE AND DETERMINATION OF THE INTRINSIC LATTICE-CONSTANTS OF GAN FREE FROM THE STRAIN [J].
DETCHPROHM, T ;
HIRAMATSU, K ;
ITOH, K ;
AKASAKI, I .
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, 1992, 31 (10B) :L1454-L1456
[5]  
EDGAR JH, 1999, PROPERTIES PROCESSIN, P264
[6]   APPLICATION OF THE MODEL OF THE RELAXATION LINE IN RECIPROCAL SPACE TO II-VI HETEROSTRUCTURES [J].
HEINKE, H ;
EINFELDT, S ;
KUHNHEINRICH, B ;
PLAHL, G ;
MOLLER, MO ;
LANDWEHR, G .
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 1995, 28 (4A) :A104-A108
[7]   Relaxation of InGaN thin layers observed by x-ray and transmission electron microscopy studies [J].
Liliental-Weber, Z ;
Benamara, M ;
Washburn, J ;
Domagala, JZ ;
Bak-Misiuk, J ;
Piner, EL ;
Roberts, JC ;
Bedair, SM .
JOURNAL OF ELECTRONIC MATERIALS, 2001, 30 (04) :439-444
[8]   InGaN-based blue light-emitting diodes and laser diodes [J].
Nakamura, S .
JOURNAL OF CRYSTAL GROWTH, 1999, 201 :290-295
[9]   X-ray powder diffraction data for indium nitride [J].
Paszkowicz, W .
POWDER DIFFRACTION, 1999, 14 (04) :258-260
[10]   Compositional pulling effects in InxGa1-x/GaN layers:: A combined depth-resolved cathodoluminescence and Rutherford backscattering/channeling study -: art. no. 205311 [J].
Pereira, S ;
Correia, MR ;
Pereira, E ;
O'Donnell, KP ;
Trager-Cowan, C ;
Sweeney, F ;
Alves, E .
PHYSICAL REVIEW B, 2001, 64 (20)