Defect formation in amorphous silicon doping superlattice films

Abstract

Doping “superlattice” amorphous silicon (a-Si:H) films have been studied using junction capacitance-voltage (C-V) and light induced electron spin resonance (LESR) measurements at a series of temperatures. Our samples vary between n-type doped and intrinsic material (nini…) on a distance scale of a few hundred Angstroms. By numerically modeling the C-V results of these measurements we can deduce the densities of both shallow and deep states in each of the constituent layers. We conclude that the deep defect density in such intrinsic regions is much greater than that in bulk intrinsic material. Further, we find evidence for distinct interface states at the doping boundaries with trapping energies which suggest they are dangling bond defects.