Author:
Weber A.,Bringmann U.,Schiffmann K.,Klages C.-P.
Abstract
ABSTRACTAluminum films deposited on silicon with MOCVD methods generally exhibit a high surface roughness due to the hindered nucleation. To decrease the nucleation barrier a pretreat-ment of the wafer with TiCl4 vapor as a chemical activator is commonly suggested.This work examines the influence of a rf hydrogen plasma on the nucleation of aluminum onSi and SiO2 using TMAA as precursor.Atomic force microscopy (AFM) was used to determine the surface roughnesses and crystallite sizes of the aluminum deposits. Without plasma activation the nucleation barrier on Si(111) is substantially higher than on oxidized Si and therefore the pretreatment of the wafer plays an important role. The hydrogen plasma causes a substantial increase of the nucleus density leading to deposits with lower surface roughnesses compared to conventionalMOCVD aluminum. The influence of the substrate on the nucleation is almost “switched off” by the plasma activation and the grain sizes of Al on Si (111) and SiO2 differ only slightly. Relatively smooth films with a resistivity of 2.7 μΩcm are obtainable by employing a plasma activated nucleation step followed by a thermal MOCVD process. The increased nucleation rate is discussed in terms of kinetic effects of plasma activation.
Publisher
Springer Science and Business Media LLC
Cited by
2 articles.
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