It was recalled that current transport through the undoped Si-rich nitride was normally limited by the contacts but, if the concentration of Si dangling bonds was increased by current-stressing or by increasing the N content, the current transport became bulk-controlled and was well-described by the Poole-Frenkel effect in a defect band. By using thin-film diode structures on p-type or n-type Si substrates, it was shown that the I-V characteristics could be explained only if current transport in the defect bands within the Si-rich nitride occurred via the movement of holes. It was concluded that hole transport through defect states was probably a common feature of all amorphous Si-rich alloys.

Hole Transport via Dangling-Bond States in Amorphous Hydrogenated Silicon Nitride. J.M.Shannon, B.A.Morgan: Journal of Applied Physics, 1999, 86[3], 1548-51