AVS 45th International Symposium
    Applied Surface Science Division Thursday Sessions
       Session AS-ThP

Paper AS-ThP12
AFM Explanation of the Improved Resolution in Auger Depth Profiles by Using the Zalar Rotation

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Aspects of Applied Surface Science Poster Session
Presenter: L. Lozzi, Università dell'Aquila, Italy
Authors: L. Lozzi, Università dell'Aquila, Italy
S. Santucci, Università dell'Aquila, Italy
D. Pacifico, Università dell'Aquila, Italy
P. Picozzi, Università dell'Aquila, Italy
R. Alfonsetti, Texas Instruments ITALIA
Correspondent: Click to Email
Auger Microscopy, as a consequence of its high lateral resolution (around 10 nm) and its sensitivity to the surface, is a powerful tool to investigate elemental and chemical composition of surfaces, interfaces and thin films, particularly in microelectronics artifacts with dimensions lower than 200 nm. In this paper we studied the TiN/AlSiCu interface, with interfacial oxygen, of a 500 nm wide metal line of a 64 Mbit DRAM device. The sharpness of this interface and the presence of interdiffused interfacial contaminants may affect the device behaviour. The elemental depth profile of the investigated system has been performed by using the Auger Spectroscopy assisted by Ar ion sputtering. The profiles have been performed using two different methods of sample sputtering: the first one maintaining the sample in a fixed position respect to the ion beam and the second one by rotating the sample with a Zalar rotation accessory. The profiles have been interrupted when the TiN/AlSiCu interface had slightly overcome. The sputtering crater has been observed by using an AFM microscope. For identical samples we observed, in the case of the fixed sputtered sample, a particularly rough TiN/AlSiCu interface with evident finger prints of preferential sputtering which produces a sensibly enlarged interface depth profile. In the case of the rotated sample, we obtained a sharp interface profile which corresponds to a flat surface of the bottom of the crater with a roughness comparable to that of the not sputtered surface. In this case the presence of interfacial oxygen bonded to Al has been carefully localised.