THE EFFECTS OF THE PROCESS PARAMETERS ON THE ELECTRICAL AND MICROSTRUCTURE CHARACTERISTICS OF THE CRSI THIN RESISTOR FILMS - PART I

The effects of process parameters, such as target composition, sputter ing pressure, reactive gas partial pressure, deposition rate, and anne al temperature, on the electrical and microstructure characteristics o f CrSi thin resistor films in very large scale integrated circuits (VL SI) application were investigated in this paper. It was observed that the higher metallic target composition, lower deposition rate, lower n itrogen partial pressure, and higher anneal temperature shift the temp erature coefficient of resistance (TCR) to the positive direction. The relationships between TCR and anneal temperature, TCR and nitrogen pa rtial pressure, and TCR and anneal environment were studied. Transmiss ion electron microscopy (TEM), and scanning electron microscopy (SEM) were conducted to explore the microstructure of the films; and the in situ anneal TEM analysis was performed to study the change of the micr ostructure of the films during anneal. The TEM images show that CrSi f ilms from sputtering have typical cermet film microstructure which con sists of darker 'island' regions embedded in lighter 'boundary medium' regions. When the anneal temperature is lower than 700 degrees C, the microstructure remains largely unchanged as the temperature increases . At 700 degrees C, the diffraction pattern from the pure Ar sputtered sample indicates that a change is occurring at 700 degrees C. No such change was observed in the reactive sputtered sample at the same temp erature. (C) 1998 Elsevier Science S.A. All rights reserved.