Abstract
In agreement with previous work,12 a thin, low temperature GaN buffer layer, that is used to initiate OMVPE growth of GaN growth on sapphire, is shown to play a critical role in determining the surface morphology of the main GaN epilayer. X-ray analysis shows that the mosaicity of the main GaN epilayer continues to improve even after several μm of epitaxy. This continuing improvement in crystal perfection correlates with an improvement in Hall mobility for thicker samples. So far, we have obtained a maximum mobility of 600 cm2/V-s in a 6 μm GaN epilayer. Atomic force microscopy (AFM) analysis of the buffer layer and x-ray analysis of the main epilayer lead us to conclude that the both of these effects reflect the degree of coherence in the main GaN epitaxial layer. These results are consistent with the growth model presented by Hiramatsu et al., however, our AFM data indicates that for GaN buffer layers partial coherence can be achieved during the low temperature growth stage.
Similar content being viewed by others
References
K. Hiramatsu, S. Itoh, H. Amano, I. Akasaki, N. Kuwano, T. Shiraishi and K. Oki,J. Cryst. Growth 115, 628 (1991).
S. Nakamura,Jpn. J. Appl. Phys. 30, L1705 (1991).
A.E. Wickenden, D.K. Wickenden and T.J. Ristenmacher,J. Appl. Phys. 75, 5367 (1994).
F. Ponce, Workshop on Wide-Gap Nitrides, St. Louis, MO, October 1994.
M.S. Goorsky, K.M. Matney, G. Chu, R. Goldman and K. Cavanagh,Advances in X-ray Analysis 39 (1995).
W. Qian, M. Skowronski, M. DeGraef, K. Doverspike, L.B. Rowland and D.K. Gaskill,Appl. Phys. Lett. 66,1252 (1995).
C.J. Sun and M. Razeghi,Appl. Phys. Lett. 63, 1 (1993).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hersee, S.D., Ramer, J., Zheng, K. et al. The role of the low temperature buffer layer and layer thickness in the optimization of OMVPE growth of GaN on sapphire. J. Electron. Mater. 24, 1519–1523 (1995). https://doi.org/10.1007/BF02676804
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02676804