Defect-pool model for doped a-Si:H

From the analysis of experimental data for P- and B-doped a-Si:H films, it is shown that the application of the standard defect-pool model to doped a-Si:H results in several discrepancies for the description of the defect distribution and concentration. A new defect-pool model for doping is presented, which is based on the substantial defect creation reaction for P and B doping. With this model it is possible to analyse the spectral shape of the defect distribution as well as the dependence of the defect concentration on the Fermi energy. The model is successfully used for the analysis of conventional doping with phosphine and diboran as well as for alternative doping with trimethylphosphine and triethylboron. Observed differences between the kind of doping and doping agents are discussed, with the H participation playing an important role.