MONTE-CARLO SIMULATIONS OF EPITAXIAL-GROWTH - COMPARISON OF PULSED-LASER DEPOSITION AND MOLECULAR-BEAM EPITAXY

The influence of epitaxial growth method on surface morphology was exp lored using a solid-on-solid, rate equation, Monte Carlo simulation wh ose parameters were chosen to approximate (1 x 1) Si (001). In simulat ions corresponding to molecular beam epitaxy, films of 10 monolayer th ickness were deposited with a steady-state flux of 0.25 monolayers/s a nd an adatom energy of 0.3 eV. In simulations corresponding to pulsed laser deposition, films of 10 monolayer thickness were deposited with a pulsed flux of 0.5 monolayers/pulse and 0.5 pulses/s and adatom ener gies ranging from 10 to 135 eV. Surface morphology was characterized u sing surface images, surface height standard deviations, and height-he ight correlation functions. In comparison to molecular beam epitaxy, p ulsed laser deposition was found to result in smaller surface roughnes s at substrate temperatures below approximately 400 degrees C and larg er surface roughness at higher temperatures. This behavior is attribut ed to a balance between roughening associated with pulsed deposition a nd smoothening associated with energetic deposition. (C) 1998 Elsevier Science B.V.