Nanometer-scale leakage measurements in high vacuum on de-processed high-k capacitors

摘要

Conductive atomic force microscopy (C-AFM) allows probing local phenomena such as trap assisted tunneling and oxide breakdown, which hamper meeting the high-k device requirements. In this work we present the improvement of Conductive AFM measurements in high vacuum (1e~(-5) torr) due to improved preservation of tip conductivity. Furthermore, we describe the gate removal process of real MOS devices, enabling standard macroscopic and microscopic measurements on the same gate dielectric. Using this procedure, we are able with C-AFM to locate the BD spots induced by standard macroscopic constant voltage stress. The C-AFM measured local current-voltage (I-V) characteristic of a single BD spot aligns well with the macroscopic post breakdown I-V trace.