Energetic Surface Smoothing of Complex Metal-Oxide Thin Films

Abstract

A novel energetic smoothing mechanism in the growth of complex metal-oxide thin films is reported from in situ kinetic studies of pulsed laser deposition of on , using x-ray reflectivity. Below 50% monolayer coverage, prompt insertion of energetic impinging species into small-diameter islands causes them to break up to form daughter islands. This smoothing mechanism therefore inhibits the formation of large-diameter 2D islands and the seeding of 3D growth. Above 50% coverage, islands begin to coalesce and their breakup is thereby suppressed. The energy of the incident flux is instead rechanneled into enhanced surface diffusion, which leads to an increase in the effective surface temperature of DeltaT approximately 500 K. These results have important implications on optimal conditions for nanoscale device fabrication using these materials.

Kinetic-energy induced smoothening and delay of epitaxial breakdown in pulsed-laser deposition

“…4(b), the intensity between pulses remains nearly constant within the noise level of RHEED signal. In PLD, intensity modulations of specularly reflected RHEED 22 and XRD 23,24 spots similar to our results, have been reported. Some of those measurements exhibit intensity recovery between pulses; this has been attributed to 4/1/07 p.10 interlayer transport 23,24 or reduction of adatom density 22 .…”

“…In PLD, intensity modulations of specularly reflected RHEED 22 and XRD 23,24 spots similar to our results, have been reported. Some of those measurements exhibit intensity recovery between pulses; this has been attributed to 4/1/07 p.10 interlayer transport 23,24 or reduction of adatom density 22 . Our observation of an insignificant intensity change during the growth interruptions between pulses following each abrupt change during a burst of deposition suggests that the surface is effectively frozen during the inter-pulse periods.…”

“…Our observation of an insignificant intensity change during the growth interruptions between pulses following each abrupt change during a burst of deposition suggests that the surface is effectively frozen during the inter-pulse periods. However, we believe that very fast athermal transport mechanisms such as adatom insertion 25 , island breakup 23 , or transient enhanced mobility of small-sized clusters on the surface 26 may still operate during or immediately following a deposition pulse in our PLD-KE. Any structural rearrangement on the surface by athermal mechanisms, as well as by thermal transport if it also operates, 27 is completed within ~1/30 second -which is the sampling rate of our RHEED intensity measurements -after a laser pulse.…”

Orientationally textured thin films of WOxdeposited by pulsed laser deposition

“…All of these potentially influence the kinetics of the film formation on the growing surface and so affect the competition between deposition and diffusion that has a strong effect on nucleation and growth [28]. Additional energy in the deposited species may activate diffusion and film crystallisation processes, however a higher rate reduces the time available for these processes to take place.…”

Initial Structure and Growth Dynamics ofYBa2Cu3O7−δduring Pulsed Laser Deposition

“…The dynamics of the growth during PLD have been extensively studied using reflection high energy electron diffraction (RHEED) [3,4]. However, with RHEED it is not possible to obtain detailed information about the atomic structure during growth, which motivated the use of x rays [5][6][7][8][9][10][11]. Here we report on x-ray diffraction measurements during the PLD growth of YBCO on SrTiO 3 001 (STO).…”