Full wafer non-contact mapping of electrical properties of ultra-thin advanced dielectrics on Si

New electrical metrology for monitoring ultra-thin gate dielectrics involves controlled deposition of thermalized ions with a corona discharge and non-contact measurement of the dielectric response with a Kelvin or Monroe type probe. We have applied this approach to measure leakage current versus oxide field (J–F) characteristics in oxides as thin as 1 nm. To measure electrical oxide thickness in the presence of direct tunneling leakage currents in such oxides we have adopted the recently introduced SASS Tox (self adjusting steady state) method, an alternative corona technique. Both the leakage current and the thickness measurements were applied to wafer scale mapping of ultra-thin SiO2.