AlN formation by direct nitrogen implantation using a DECR plasma

Abstract

Nitriding of aluminum was carried out successfully using a distributed electron cyclotron resonance (DECR) nitrogen plasma without RF bias voltage or heating of the substrate. The surface compositions and chemical environments of the treated samples were characterized by X-ray photoelectron and Auger spectroscopy (XPS-XAES). AlN formation was evidenced. Ar+ etching sequences in the ultra high vacuum chamber of the spectrometer allowed us to investigate the internal nature of the samples, and to estimate the nitride layer 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%)+H2(10%)] plasma followed by a [N2(96%)+Ar(4%)] plasma allowed us to nitride 60% of the whole detected aluminum. For this sample, the nitride layer thickness was estimated to 22Å.