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.