Hydrogen release at metal-oxide interfaces: A first principle study of hydrogenated Al/SiO2 interfaces

Abstract The Anode Hydrogen Release (AHR) mechanism at interfaces is responsible for the generation of defects, that traps charge carriers and can induce dielectric breakdown in Metal-Oxide-Semiconductor Field Effect Transistors. The AHR has been extensively studied at Si/SiO 2 interfaces but its characteristics at metal-silica interfaces remain unclear. In this study, we performed Density Functional Theory (DFT) calculations to study the hydrogen release mechanism at the typical Al/SiO 2 metal-oxide interface. We found that interstitial hydrogen atoms can break interfacial Al Si bonds, passivating a Si sp 3 orbital. Interstitial hydrogen atoms can also break interfacial Al O bonds, or be adsorbed at the interface on aluminum, forming stable Al H Al bridges. We showed that hydrogenated O H, Si H and Al H bonds at the Al/SiO 2 interfaces are polarized. The resulting bond dipole weakens the O H and Si H bonds, but strengthens the Al H bond under the application of a positive bias at the metal gate. Our calculations indicate that Al H bonds and O H bonds are more important than Si H bonds for the hydrogen release process.