On the importance of electron–electron scattering for hot-carrier degradation

Abstract

Using our physics based model for hot-carrier degradation (HCD) we analyze the importance of the effect of electron–electron scattering (EES) on HCD in transistors with different channel lengths. The model is based on a thorough treatment of carrier transport and is implemented into the deterministic Boltzmann transport equation solver ViennaSHE. Two competing mechanism of Si–H bond-breakage are captured by the model: the one triggered by the multiple vibrational excitation of the bond and another which is due to excitation of one of the bonding electrons to an antibonding state by a solitary hot carrier. These processes are considered self-consistently as competing pathways of the same dissociation reaction. To analyze the importance of the EES process we use a series of nMOSFETs with identical architecture but different gate lengths. The gate length varies in the wide range of 44–300 nm to cover short-channel MOSFETs as well as their longer counterparts. According to previous findings, EES starts to become important at a channel length of 180 nm. This situation is captured in the targeted gate length interval. Our results show that the channel length alone is not a sufficient criterion on the importance of EES and that the applied bias conditions have to be taken into account as well.

The impact of self-heating and its implications on hot-carrier degradation – A modeling study

“…A possible explanation for this change of the temperature behavior (which was suggested to occur at channel lengths less than ∼100 nm) is that in scaled devices carrier-carrier interactions become the dominant scattering mechanism, while other scattering mechanisms are suppressed [14,15]. Carrier-carrier interactions are considered to populate the high energetic tail of the carrier spectrum [14,[16][17][18][19] -i.e., accelerate HCD -and the rate of this process is an increasing function of T . However, recent findings have demonstrated that the temperature dependence of HCD is nonuniversal and is determined by the device geometry and stress conditions [20][21][22].…”

Oxide-defects driven study on reliability and synaptic response characterization of logic devices

“…xvii 2-12 A schematic representation of combinations of MVE-and ABmechanisms. It means that the bond can be firstly excited to an intermediate level i by several colder carriers and then dissociated by a solitary high energetical carrier [112].…”

“…This is referred to as the MVE process [105], [110], [111]. With a modification in the model, the real scenario of the Si-H bond breakage comprises a combination of the single-and multiple-carrier processes, as shown in Figure 2-12 [112].…”