Degradation and Breakdown of Ultrathin Gate Oxide

120 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2001.For ultrathin oxides, a new type of failure mode, soft breakdown, has been observed. The characteristics of this kind of failure are often identified by a large increase of gate signal noise level. It has been proposed that there is a threshold power that divides soft and hard breakdown. In this thesis, time-to-breakdown of ultrathin gate oxide is tested, and the power dissipation after breakdown is obtained. Based on the critical power value that separates the soft and hard breakdown, thermal simulation is done using finite element analysis. The effects of interfacial thermal resistance and nanoscale heat conduction are included in the thermal model. The simulation results show that the diameter of leakage path is between 0.1 and 0.5 nm in order to raise the temperature close to glass transition temperature of SiO2. At this temperature, the structure change of SiO2 could leads to the breakdown of oxide.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD