A technique and precision instrumentation developed for rapid characterization of dielectric layers is described. It involves the use of a kinematically stable, flattened probe placed directly on the dielectric layer formed on top of a conducting substrate. This technique does not involve device fabrication and hence avoids any fabrication-induced changes in the dielectric layer. Electrical characterization involves static I-V measurements to breakdown, self-healing behaviour, charge to breakdown and time to breakdown distributions in constant current and constant voltage modes. The technique was used to characterize thin (38 nm) silicon dioxide films and also relatively thick (320 nm) buried oxide layers in two types of SIMOX SOI (separation by implanted oxygen - silicon on insulator) substrates. The I-V study clearly showed that SIMOX oxides formed by the multiple oxygen implantation process are superior to those formed by a single oxygen implantation step.