A new automated metrology tool using infrared spectroscopic ellipsometry is presented. After a description of the instrument with special attention on the spot size, the instrument specifications are described and one application of the technique related to the IC technology is presented. We show that physical and electrical information on Ultra Shallow Junction formed by Excimer Laser annealing for the sub 100 nm node on silicon on insulator (SOI) and on bulk silicon can be obtained independently. We compare these results with conventional techniques like four points probe and secondary ion mass spectroscopy (SIMS) and show a very good agreement. (C) 2004 Elsevier B.V. All rights reserved.