Surface Planarization with Gas Cluster Ion Beams and Application to Wide-Bandgap Semiconductors
Graduate School of Engineering, University of Hyogo
2167 Shosha, Himeji, Hyogo 671-2280, Japan
In this study, the fundamental sputtering effects of gas cluster ion beams (GCIBs), especially for surface planarization, are reported. Because gas cluster ions are aggregates of thousands of gas atoms, the collision process for a GCIB, with dense and multiple collisions, differs from that of atomic ions via collision cascading; thus, GCIBs have many unique irradiation effects. Among them, the low-damage and surface smoothing effects are beneficial for the planarization of wide-bandgap semiconductor wafers. The planarization of SiC, diamond, and GaN has been demonstrated using GCIB irradiation.
-  I. Yamada, “New horizons in material processing with ICB,” Proc. of the 14th symposium on ion sources and ion-assisted technology, The ion engineering society of Japan, Tokyo, pp. 227-235, 1991.
-  Z. Insepov and I. Yamada, “Molecular dynamics simulation of cluster ion bombardment of solid surface,” Nucl. Instr. and Meth. B, Vol.99, pp. 248-252, 1995.
-  N. Toyoda and I. Yamada, “Gas cluster ion beam equipment and applications to surface processing,” IEEE Trans. on Plasma Science, Vol.36, pp. 1471-1488, 2008.
-  P. Sigmund, “Theory of Sputtering. I. Sputtering Yield of Amorphous and Polycrystalline Targets,” Phys. Rev., Vol.184, pp. 383-416, 1969.
-  T. Aoki, J. Matsuo, Z. Insepov, and I. Yamada, “Molecular dynamics simulation of damage formation by cluster ion impact,” Nucl. Instr. and Meth. B, Vol.121, pp. 49-52, 1997.
-  N. Toyoda, H. Kitani, N. Hagiwara, J. Matsuo, and I. Yamada, “Surface smoothing effects with reactive cluster ion beams,” Mat. Chem. and Phys., Vol.54, pp. 106-110, 1998.
-  C. L. Cleveland and U. Landman, “Dynamics of Cluster-Surface Collisions,” Science, Vol.257, pp. 355-361, 1992.
-  I. Yamada, J. Matsuo, N. Toyoda, T. Aoki, E. Jones, and Z. Insepov, “Non-linear processes in the gas cluster ion beam modification of solid surfaces,” Mat. Sci. and Eng. A, Vol.253, pp. 249-257, 1998.
-  N. Toyoda and I. Yamada, “Nano structure formation by gas cluster ion beam irradiations at oblique incidence,” Mater. Res. Soc. Symp. Proc., Vol.849, pp. 109-113, 2005.
-  A. Yoshida, M. Deguchi, M. Kitabatake, T. Hirao, J. Matsuo, N. Toyoda, and I. Yamada, “Atomic level smoothing of CVD diamond films by gas cluster ion beam etching,” Nucl. Instr. and Meth. B, Vol.112, pp. 248-251, 1996.
-  N. Toyoda and I. Yamada, “High-precision processing with gas cluster ion beams,” J. of the Japan Society for Precision Engineering, Vol.82, p. 315, 2016.
-  T. Aoki, J. Matsuo, G. Takaoka, and I. Yamada, “Cluster species and cluster size dependence of damage formation by cluster ion impact,” Nucl. Instr. and Meth. B, Vol.206, pp. 861-865, 2003.
-  C. Eggs, E. Schmidhammer, and A. Schaufele, “Yield enhancement for BAW production using local corrective etching,” Proc. of workshop on cluster ion beam process technology, pp. 46-51, 2006.