Saturday, May 2, 2015

Spatial ALD vs Temporal ALD - HERALD workshop on Fundamentals of ALD at TU/e

As reported earlier, there will be a Cost Action "HERALD" workshop on Fundamentals of ALD - June 8 & 9, Eindhoven organized by Erwin Kessels Professor in Applied Physics at Eindhoven University of Technology. June 8 (start at noon) to June 9 (end mid-afternoon). Please see .

One of the sessions will be on Spatial ALD vs Temporal ALD as described by this two pager (here) and briefly summarized below. 

"Spatial Atomic Layer Deposition is an ALD method that emerged the past few years, allowing high throughput ALD for a number of applications and processes. It relies on a spatial separation of precursor exposures instead of temporal separation in conventional ALD. Spatial ALD has found use particular in large - area and/or flexible electronics, such as photovoltaics, OLED lighting and displays, where the unique qualities of ALD are a clear asset, but where high throughput processing (e.g, roll-to-roll) is required. There are several different ways to do Spatial ALD (atmospheric vs low-pressure, R2R, S2S, plasma, etc.)but in all cases it is an equipment enabled method and they share a common feature: it is all ALD."

A Spatial ALD reaction scheme where the precursors are dosed simultaneously and continuously in half-reaction precursor zones separated by inert gas zones. Moving the substrate through two half-reaction zones completes one ALD cycle (Poodt et al., J. Vac. Sci. Technol. A 30, 010802 (2012))

The following topics will be addressed during the introduction:
  • Basic introduction Spatial ALD and comparison with conventional ALD
  • Time scales in ALD, and what does “deposition rate” mean in ALD
  • Atmospheric vs. low-pressure ALD
  • Kinetics of Spatial ALD
  • The balance between deposition rate, uniformity, performance and costs