Atomic Layer Deposition of Aluminum Thin Films Using an Alternating Supply of Trimethylaluminum and a Hydrogen Plasma

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Abstract
The atomic layer deposition (ALD) of aluminum films using trimethylaluminum [TMA, and a hydrogen plasma was examined to improve the surface morphology with good step coverage. The most important role of the hydrogen plasma was to act as a reducing agent for TMA. The film properties were analyzed using field-emission scanning electron microscopy, atomic force microscopy, Rutherford backscattering spectroscopy, and elastic recoil detection-time of flight. The growth rate was saturated at and the thickness was proportional to the number of reaction cycles. Repeating this reaction cycle led to controlled layer-by-layer growth. The root-mean-square roughness value of a 7.5 nm thick Al film was 0.195 nm, and ALD films had excellent step coverage on high aspect ratio trenches. © 2002 The Electrochemical Society. All rights reserved.