Substrate Hot-carrier Injection Research Articles

The TDDB Characteristics of Ultra-Thin Gate Oxide MOS Capacitors under Constant Voltage Stress and Substrate Hot-Carrier Injection

The breakdown characteristics of ultra-thin gate oxide MOS capacitors fabricated in 65 nm CMOS technology under constant voltage stress and substrate hot-carrier injection are investigated. Compared to normal thick gate oxide, the degradation mechanism of time-dependent dielectric breakdown (TDDB) of ultra-thin gate oxide is found to be different. It is found that the gate current (Ig) of ultra-thin gate oxide MOS capacitor is more likely to be induced not only by Fowler-Nordheim (F-N) tunneling electrons, but also by electrons surmounting barrier and penetrating electrons in the condition of constant voltage stress. Moreover it is shown that the time to breakdown (tbd) under substrate hot-carrier injection is far less than that under constant voltage stress when the failure criterion is defined as a hard breakdown according to the experimental results. The TDDB mechanism of ultra-thin gate oxide will be detailed. The differences in TDDB characteristics of MOS capacitors induced by constant voltage stress and substrate hot-carrier injection will be also discussed.

Effects of Electron Current and Hole Current on Dielectric Breakdown in HfSiON Gate Stacks

The roles of electrons and holes in the dielectric breakdown of HfSiON have been investigated by controlling the numbers of injected hot electrons and hot holes separately by the substrate hot-carrier injection technique. It has been clarified that carrier flux has the strongest effect on the dielectric breakdown of HfSiON rather than carrier energy and the electric field across dielectrics. The amount of electron flux leading to the dielectric breakdown of HfSiON is about twice as large as that of hole flux.

EXPERIMENTAL ANALYSIS AND PHYSICAL MODEL INVESTIGATION OF TDDB OF THIN GATE OXIDE

Breakdown character of thin SiO2 is investigated by using substrate hot-carrier injection techniques. Hot-carrier induced thin gate oxide damaged shows different breakdown character compared with the case of conventional F-N tunneling experiments.Good correlation between the calculated electron energy in the oxide and the electric field in the silicon substrate suggests that the difference between hot-electron injection and the F-N tunneling can be explained in terms of the average electron energy in the oxide.Hot holes injection experiments reveal that the life of oxide breakdown is not simply determined by the total number of injected holes.New hot-carrier-induced TDDB (Time-dependent dielectric breakdown)models of thin gate oxide are reported in this paper.

Effect of substrate hot-carrier injection on quasibreakdown of ultrathin gate oxide

The quasibreakdown (QB) of ultrathin gate oxide under substrate hot-hole and -electron injection was investigated. It has been found that hot-carrier injection greatly degrades the immunity to the QB and the hot hole is more effective than the hot electron in the degradation. The phenomenon was explained by an interface damage-controlled mechanism and verified again by monitoring the interface state densities at the onset point of QB. It also has been found that QB occurs when the interface state density reaches a critical value, regardless of the stress current density and stressing carrier type.