PtSi Contact Metallurgy using Sputtered Pt and Different Annealing Processes

PtSi contacts have been formed by different annealing processes using sputtered Pt. Two annealing sequences are compared: a single-temperature one at 550°C and a three-temperature one at 200°-300°-550°C. Three annealing ambients are compared for each sequence: forming gas, nitrogen, and oxygen. The process using the three-temperature sequence in forming gas differs from all the others in that it allows a complete reaction between Pt and Si, leaving a thin passivating oxide layer with excellent protection against etching in aqua regia, a desirable step in device fabrication. PtSi films formed by all the other processes, on the other hand, show incomplete reactions between Pt and Si, with a thicker but very poor surface oxide layer which is completely etched off by aqua regia. Film structures and composition are analyzed, Schottky diodes fabricated from different processes are measured, and the results are discussed. © 1986, The Electrochemical Society, Inc. All rights reserved.