Effective transition rates for epitaxial growth using fast modulation

Abstract

Thin-film deposition is an industrially important process that is highly dependent on the processing conditions. Most films are grown under constant conditions, but a few studies show that modified properties may be obtained with periodic inputs. However, assessing the effects of modulation experimentally becomes impractical with increasing material complexity. Here we consider periodic conditions in which the period is short relative to the time scales of growth. We analyze a stochastic model of thin-film growth, computing effective transition rates associated with rapid periodic process parameters. Combinations of effective rates may exist that are not attainable under steady conditions, potentially enabling new film properties. An algorithm is presented to construct the periodic input for a desired set of effective transition rates. These ideas are demonstrated in three simple examples using kinetic Monte Carlo simulations of epitaxial growth.

Temperature-dependent 2-D to 3-D growth transition of ultra-thin Pt films deposited by PLD

“…These prerequisites are met for metal growth by pulsed laser depoa) The authors wish to acknowledge financial supported by the Swiss Bundesamt für Energie (BfE) and Swiss Electric Research (SER) and would like to thank Ulrich Müller (Scanning Probe Microscopy User Laboratory, Empa) for his support. b) Electronic mail: henning.galinski@mat.ethz.ch; http://www.nonmet.mat.ethz.ch sition (PLD) 8,9 , so called laser-MBE, especially in case of the large ratios between the pulse duration (≈ 10−25 ns) and the repetition rate (≈ 1−100 Hz). This circumstance makes PLD ideal for surface-engineering 10 and for studying the fundamentals of metal-on-insulator growth.…”

Physical time scale in kinetic Monte Carlo simulations of continuous-time Markov chains

“…For instance, Bellon and Martin [12] suggested that the connection between KMC and absolute times in rejection algorithms is empirical. Many other authors have also pointed out, in some way, the lack of a formal connection between time scales [13].We prove here that rejection-free algorithms are simply a limiting case of a generic class of KMC algorithms, which include the rejection algorithms as well. Simultaneously with the proof, we naturally derive a physical time scale for this generic class of algorithms, which is thus valid for both rejection and rejection-free KMC.…”

“…For instance, Bellon and Martin [12] suggested that the connection between KMC and absolute times in rejection algorithms is empirical. Many other authors have also pointed out, in some way, the lack of a formal connection between time scales [13].…”