EFFECT OF AMMONIA VAPORS ON THE SURFACE CURRENT IN SILICON P-N JUNCTIONS

Abstract

I V characteristics of forward and reverse currents in silicon p-n junctions were measured in air, in air with ammonia vapors at several partial pressures of NH3, as well as in air after ammonia vapors treatment. The influence of adsorbed ammonia molecules on the forward current is explained by such processes: a) an increase in the surface re- combination rate, caused by the electric field of ammonia ions, which are localized on the external side of the natural oxide layer; b) etching out some surface recombination states. The changes in the forward and reverse currents are reversible, so silicon p-n junctions can be used as ammonia vapors sensors.