Measurement of the mobile ion concentration in the oxide layer of a semiconductor wafer

摘要

A method and apparatus for measuring the concentration of mobile ions in the oxide layer of a semiconductor wafer from the contact potential shift caused by ion drift across the oxide that includes depositing charge (e.g., using a corona discharge device) on the surface of the oxide and heating the wafer to allow mobile ions in the oxide (especially Na+) to drift. The difference in the contact potential measured before and after heating provides an indication of the mobile ion concentration in the oxide layer.