Chemistry of Hydrogen Interactions at Grain Boundaries

The chemistry involved in the incorporation of hydrogen in polycrystalline Si grains and grain boundaries is investigated. Volume-indexed surface analysis techniques (SIMS and AES) are utilized for the identification of the impurity species (elemental or molecular), the evaluation of their concentrations and the determination of their exact spatial locations. The reactions of the hydrogen with the ion-modified Si surface and the grain boundaries are examined for both oxygen-deficient and oxygen-rich intergrain regions. Three bonding schemes are identified, namely mono- and di-hydride and hydroxyl. Thermal desorption and electron desorption spectroscopies complement the surface analytical investigations.