Growth modes and microstructures of ZnO layers deposited by plasma-assisted molecular-beam epitaxy on (0001) sapphire

Journal of Applied Physics - Tập 90 Số 10 - Trang 5115-5119 - 2001
F. Vigué1, P. Vennéguès1, C. Deparis1, S. Vézian1, M. Laügt1, J. P. Faurie1
1Centre de Recherche sur l'Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, (CRHEA/CNRS), Rue Bernard Grégory, Parc Sophia Antipolis, F-06560 Valbonne, France

Tóm tắt

Transmission electron microscopy and high resolution x-ray diffraction are used to characterize defects in ZnO layers grown by plasma-assisted molecular-beam epitaxy on (0001) sapphire. Two- and three-dimensional types of growth modes are described and the observed mosaic structure is analyzed in each case. It is found that two-dimensional layers exhibit a roughness as low as 6 nm. Their subdomains have small lateral coherence lengths and a mean in-plane misorientation of ±0.4°, leading to an important dislocation density of 1–4×1010 cm−2. On the contrary, it is demonstrated that, through numerous interactions between dislocations, the three-dimensional growth mode leads to a better structural quality with a larger lateral coherence length and a smaller in-plane mosaic spread of ±0.07°. The total dislocation density is consequently reduced by 1 order of magnitude down to 3–5×109 cm−2 and the radical modification of the structure results in a change of the dislocation distribution. Our results thus demonstrate that two-dimensional growth mode and low full width at half maximum for symmetric x-ray diffraction are a not reliable indicator of a good structural quality.

Từ khóa


Tài liệu tham khảo

1997, Appl. Phys. Lett., 70, 2230, 10.1063/1.118824

2001, Appl. Phys. Lett., 78, 3385, 10.1063/1.1375830

1997, J. Vac. Sci. Technol. A, 15, 1103, 10.1116/1.580437

1994, Appl. Phys. Lett., 65, 2963, 10.1063/1.112478

1996, J. Electron. Mater., 25, 855, 10.1007/BF02666649

1999, J. Cryst. Growth, 201/202, 627, 10.1016/S0022-0248(98)01427-4

2000, Appl. Phys. Lett., 76, 559, 10.1063/1.125817

1996, Appl. Phys. Lett., 68, 643, 10.1063/1.116495

1998, J. Appl. Phys., 84, 3912, 10.1063/1.368595

2000, J. Cryst. Growth, 209, 532, 10.1016/S0022-0248(99)00614-4

1998, Jpn. J. Appl. Phys., Part 1, 37, 781, 10.1143/JJAP.37.781

2001, J. Vac. Sci. Technol. B, 19, 506, 10.1116/1.1349210

2001, Appl. Phys. Lett., 79, 196

1998, J. Appl. Phys., 83, 1379, 10.1063/1.366840

1998, J. Cryst. Growth, 187, 167, 10.1016/S0022-0248(97)00875-0

1996, Jpn. J. Appl. Phys., Part 2, 35, L1648, 10.1143/JJAP.35.L1648

Thông tin
Thông tin xuất bản

Journal of Applied Physics

Tập 90 Số 10

5115-5119

Thông tin tác giả