AlN formation by direct nitrogen implantation using a DECR plasma

Nitriding of aluminum was carried out successfully using a distributed elec tron cyclotron resonance (DECR) nitrogen plasma without RF bias voltage or heating of the substrate. The surface compositions and chemical environment s of the treated samples were characterized by X-ray photoelectron and Auge r spectroscopy (XPS-XAES). AlN formation was evidenced. Ar+ etching sequenc es in the ultra high vacuum chamber of the spectrometer allowed us to inves tigate the internal nature of the samples, and to estimate the nitride laye r thickness. It is shown that the residual oxide layer acts as a diffusion barrier. An efficient in situ preliminary cleaning was researched in order to get a high nitriding rate. An [Ar(90%)+H-2(10%)] plasma followed by a [N -2(96%)+Ar(4%)] plasma allowed us to nitride 60% of the whole detected alum inum. For this sample, the nitride layer thickness was estimated to 22 Angs trom. (C) 2000 Elsevier Science S.A. All rights reserved.