Interaction of Hydrogen with Silicon-Silicon Dioxide Interfaces

Hydrogen released by ionizing radiation reacts with hydrogen- passivated Si dangling bonds at the Si-SiO$_{2}$ interface to create interface traps (Pb-centers) in Si semiconductor devices. For certain bipolar transistors the resultant gain degradation increases as the dose rate is reduced for a given total dose of ionizing radiation. This phenomenon is known as Enhanced Low Dose Rate Sensitivity (ELDRS). In this presentation, the interaction of the hydrogen with the interface and with the dangling bonds will be discussed. Our results are obtained from electronic structure calculations (SeqQuest) on supercell models of silicon dioxide and its interface with silicon. These results provide boundary conditions for hydrogen interaction with the interface that are used for continuum calculations of the interface trap density dependence on radiation dose rate.