Role of hydrogen at germanium/dielectric interfaces

Hydrogen is an indispensable ingredient in integrated-circuit fabrication, since it is used to passivate defects at the Si/SiO2 interface present in every CMOS transistor. Hydrogen will likely play an equally important role for the novel channel materials and dielectrics that are currently being investigated. We show that first-principles calculations can produce fundamental information about the behavior of hydrogen in relevant semiconductors and oxides. We point out the link between the electronic structure of hydrogen and the band-alignment problem, and specifically highlight why hydrogen at interfaces with germanium will exhibit a very different behavior from what is known to happen in silicon.