On the field enhanced carrier generation in mos structures

Using a sine voltage sweep C-V, DLTS, gettering and defect revealing techniques the thermal carrier generation in MOS (Metal - Oxide - Semiconductor) structures was investigated. The thermal generation from a field dependent becomes as field independent due to the gettering. The activation energy of generation - recombination centers, E-alpha, the generation lifetime, tau(g), and Poole-Frenkel factor, alpha, were determined. Dislocations with an average density of 5 x 10(6) cm(-2) were observed in all wafers. In the samples with field enhanced carrier generation a linear dependence between E-alpha and alpha was found, where the Poole-Frenkel factor increases with the increase of the activation energy. On the other hand E-alpha, tau(g) and alpha were found to be strongly affected by the gettering, thereby suggesting that they depend on the level of decoration of the dislocations with impurities.