Thermal instability of Schottky diode barrier heights modified by inert ion sputter-etching damage

The barrier height of Schottky diodes made to dry-etched silicon surfaces differs from those fabricated on wet chemically etched silicon. Some have suggested utilization of this phenomenon to yield diodes for VLSI applications that display barrier enhancement to p-type silicon and barrier reduction to n-type silicon together with good diode ideality factors; however, it is shown here that the modified barrier heights can be dramatically unstable even when exposed to relatively low-temperature cycling, thus rendering this technique of enhancing the barrier height to p-type silicon and reducing the barrier height to n-type silicon inappropriate for conventional VLSI fabrication. It is hypothesized that the barrier instability is due to a localized silicide reaction or surface reconstruction occurring at the metal/silicon interface.