Abnormal Relationship Between Hot Carrier Stress Degradation and Body Current in High-k Metal Gate in the 14-nm Node

This letter discusses the hot carrier stress (HCS) degradation mechanisms for different gate voltages (
$\text{V}_{\textsf {G}}$
) in FinFET devices, and finds the abnormal relationship between HCS degradation and body current under high
$\text{V}_{\textsf {G}}$
. According to the distributions of lifetime (
${\tau }$
)-
$\text{I}_{\textsf {B}}$
and
${\tau }$
-drain current (
$\text{I}_{\textsf {D}}$
), it is found that the
${\tau }$
under the high
$\text{V}_{\textsf {G}}$
is related to the
$\text{I}_{\textsf {D}}$
instead of the
$\text{I}_{\textsf {B}}$
. In addition, as the
$\text{V}_{\textsf {G}}$
increases from low to middle to high values, the HCS degradation mechanism exhibits single vibrational excitation, electron-electron scattering, and multiple vibrational excitation (MVE) models, respectively. Therefore, the HCS degradation mechanism at higher
$\text{V}_{\textsf {G}}$
is not dominated by the traditional impact ionization but by the carrier concentration of the channel. Finally, according to the results of fitting MVE model, the reason for breaking the Si-H bonds to form dangling bonds is the bending vibrational mode.