| AVS 66th International Symposium & Exhibition | |
| Thin Films Division | Monday Sessions |
| Session TF+2D+AP+EL+SS-MoA |
| Session: | ALD and CVD: Nucleation, Surface Reactions, Mechanisms, and Kinetics |
| Presenter: | Jeffrey M. Woodward, ASEE (residing at US Naval Research Laboratory) |
| Authors: | J.M. Woodward, ASEE (residing at US Naval Research Laboratory) S.G. Rosenberg, American Society for Engineering Education (residing at US Naval Research Laboratory) S.D. Johnson, U.S. Naval Research Laboratory N. Nepal, U.S. Naval Research Laboratory Z.R. Robinson, SUNY Brockport K.F. Ludwig, Boston University C.R. Eddy, U.S. Naval Research Laboratory |
| Correspondent: | Click to Email |
Indium aluminum nitride (InAlN) is an attractive material for power electronic applications. However, conventional methods of epitaxial growth of InAlN are challenged by a large miscibility gap and the significant differences in optimal growth conditions for the constituent aluminum nitride (AlN) and indium nitride (InN) binary compounds. Despite these challenges, the epitaxial growth of InAlN alloys throughout the entire compositional range has been demonstrated using plasma-assisted atomic layer epitaxy (ALEp)1, a variant of atomic layer deposition in which relatively higher temperatures are utilized. In the ALEp growth of InAlN, the desired alloy compositions are achieved by forming ultra-short period superlattices of alternating InN and AlN layers, referred to as digital alloys (DA). In order to further advance these empirical efforts, significant research is needed to better understand the nucleation and growth kinetics of ALEp DA growth. To this end, we employ in situ grazing incidence small angle X-ray scattering (GISAXS) for the real-time study of the evolving ternary InAlN surfaces as has been done previously for binary InN2 and AlN3.
Here we present in situ GISAXS studies of ALEp growth of InN, AlN, and a range of InAlN DAs on GaN (0001) substrates, which were performed at Brookhaven National Laboratory’s NSLS-II using a custom reactor. The InAlN DAs studied include In0.19Al0.81N (3 AlN cycles and 2 InN cycles per supercycle), In0.5Al0.5N (1 AlN cycle and 3 InN cycles per supercycle), In0.64Al0.36N (1 AlN cycle and 5 InN cycles per supercycle) and In0.83Al0.17N (1 AlN cycle and 14 InN cycles per supercycle). Preliminary analysis of the data suggests that while the pure InN and AlN grew in 3D and 2D modes, respectively, the InAlN growth mode did not follow a simple trend as the nominal composition was tuned from InN to AlN. Instead, select compositions (50% and 83% In) exhibited predominantly 3D growth, while others (19% and 64% In) exhibited 2D growth. We also present complementary ALEp growth studies using a commercial Ultratech/Cambridge Nano Tech Fiji 200 and ex situ characterization methods, including high resolution X-ray diffraction, X-ray reflectivity, and atomic force microscopy.
1 N. Nepal, V.R. Anderson, J.K. Hite, and C.R. Eddy, Thin Solid Films 589, 47 (2015)
2 J.M. Woodward, S.G. Rosenberg, A.C. Kozen, N. Nepal, S.D. Johnson, C. Wagenbach, A.H. Rowley, Z.R. Robinson, H. Joress, K.F. Ludwig Jr, C.R. Eddy Jr, J. Vac. Sci. Technol. A 37, 030901 (2019)
3 V.R. Anderson, N. Nepal, S.D. Johnson, Z.R. Robinson, A. Nath, A.C. Kozen, S.B. Qadri, A. DeMasi, J.K. Hite, K.F. Ludwig, and C.R. Eddy, J. Vac. Sci. Technol. A 35, 031508 (2017)