Reliability Studies of LSI Arrays Employing Al-Si Schottky Barrier Devices

Recently digital bipolar LSI arrays employing Al-Si Schottky barrier devices have become commercially available. The introduction of a novel semiconductor component in a complex array can raise special reliability questions; the purpose of this work is to investigate the reliability of Al-Si Schottky barrier devices and LSI arrays employing such components. The Schottky barrier devices in these new arrays are primarily employed as clamps on the collector-base junctions of n-p-n switching transistors. In this way, significant forward biasing of the collector-base junction is inhibited, and so minority carrier injection and storage in the collector region is prevented. Thus, the need for lifetime control by gold doping is eliminated; amoung the significant advantages thereby resulting are: - Availability of a much greater variety of device types in the same array. - Simpler and more reproducible processing. In this paper the characteristics and fabrication of Al-Si Schottky barrier devices are first reviewed; then, the results of reliability studies are presented in detail.