Theoretical evaluation of film growth rate during atomic layer epitaxy

The film growth rate of atomic layer epitaxy (ALE) was explored with the macroscopic consideration using the concept of fractional coverage exchange. The theoretically evaluated film thickness per deposition cycle showed the dependence upon the quantity of adsorbate that is highly related with the surface coverage of each element. The model can confirm that the periodic boundary condition of the surface coverage during a cyclic deposition is satisfied after the transition period in which the initial substrate is still influencing the film deposition. The efficiency of film deposition with the variation of elapsed time per deposition cycle was evaluated using the model. It is shown that the present model is capable of interpreting the ALE growth including the case in which growth rate is less than 1 monolayer per deposition cycle (ML/cycle). (C) 2000 Elsevier Science B.V. All rights reserved.