IN-SITU MONITORING OF ELECTROCHEMICAL PROCESSES AT THE (100)P-SI AQUEOUS NH4(F) ELECTROLYTE INTERFACE BY PHOTOLUMINESCENCE/

Photoluminescence (PL) with short N-2-laser pulses is a plied for in s itu monitoring of electrochemical processes at the (100) p-Si/aqueous NH4F electrolyte interface during anodic oxidation followed by electro chemical hydrogenation at low cathodic potential. The anodic oxidation is carried out in a potential regime where electropolishing with curr ent oscillations occurs. The etch rate of the anodic oxide, which is c haracterized by the reciprocal oscillation period(10) is changed by th e composition of the fluoride solution. At the minimum of the current oscillations the PL intensity increases with decreasing etch rate and anticorrelates with the oxidation rate, which is monitored by the curr ent. The hydrogenation of the Si surface is characterized by the anodi c current transient. The PL intensity increases strongly during the de cay of this transient.