In-situ STM observation of the initial stage of the film growth

I. Kataoka, K. Sekine, K. Etoh, K. Ito, S. Hirayama, K. Nishimoto

Central Research Laboratory, Japan Aviation Electronics Industry, Ltd.
1-1 Musashino 3-chome Akishima-shi Tokyo 196 Japan

  The methods of deposition with energetic particles as dual ion beam 
sputtering (DIBS) and low energy direct ion beam deposition (LDIBD) have been 
investigated to develop multilayer structures for soft-Xray optics, because 
those are thought to be suitable to get smooth amorphous films with high 
packing density. In order to improve interface roughness of those 
multilayers, the mechanism of film growth with energetic particles has been  
studied. As part of the study, we  developed a system to observe an initial 
stage of film formation by low energy ions in detail, combining an ultra-high 
vacuum scanning tunneling microscope (UHV-STM) and an ion beam assembly.
  In this paper we show the recent results of the observation of surfaces 
irradiated by low energy ions with the above mentioned system. The HOPG 
substrates were irradiated by C+ ions with energy from 25 eV to 150 eV and to 
the amount of 1,4,10 uC respectively at room temperature. As a result it was 
found that small carbon clusters are formed on the surfaces in the initial 
stage and incident atoms tend to be absorbed on a little bit off from the 
lattice points of the HOPG shown in Figure 1. The number of clusters is 
decreasing as the ion energy decreases until it reaches to the damage 
threshold in the energy range below 50 eV, but in the higher energy region 
the number is increasing as the energy decreases. Also the shapes of 
clusters, generation of defects and other subjects will be shown in my talk.