Mechanism Of Defect Reactions In Semiconductors

An overview is presented on mechanisms of electronically induced (enhanced) defect reactions in semiconductors, which are classified into the local heating, the structural instability, and the recombination enhanced. A mechanism for the annihilation of a hydrogen-carbon complex in silicon is given as an example of the second one. The last two mechanisms can be treated in a unified scheme by using the correct configuration coordinate diagram, which enable us to treat correctly the correlation in successive captures of an electron and a hole. The energy conversion mechanism during the reaction is precisely discussed paying attention to the relation between the lattice relaxation mode and the symmetry breaking reaction coordinate.

Alternative Mechanism for Defect Generation in a-Si:H

ABSTRACTRecombination-driven mechanisms for defect formation do not account well for several experimental facts, and indeed conflict with some facts. To overcome these problems, an alternative mechanism is proposed in which latent defect centers are converted to metastable defects (dangling bonds) without a recombination event. The transitions are driven simply by electron capture at the center with no energy barrier. A new configuration-coordinate diagram expressing this mechanism includes essential configuration-induced changes in the energies of band edges, and accounts for several other previously problematic observations. This carrier-induced mechanism (CIM) is consistent with defect formation in forward bias and defect inhibition in reverse bias, light-enhanced annealing, as well as the usual light-induced and beam-induced formation. For low orħħωthe process starts by ionization of an existing defect.