Hydrogen effusion from hydrogenated amorphous silicon caused by the deposition of a silicon nitride overlayer

Abstract
The effect of silicon nitride (SiN) deposition on hydrogenated amorphous silicon (a‐Si:H) has been investigated to find the origin of the difference of a‐Si:H/SiN interface properties caused by the order of deposition. Sheet conductance of the on‐state in inverted staggered (a‐Si:H on SiN) thin‐film transistors (TFTs) increases gradually with the substrate temperature (Tsub) of SiN, but decreases rapidly with the Tsub of SiN in staggered TFTs (SiN on a‐Si:H). Photoluminescence experiments indicated that the degradation in staggered TFTs was due to the creation of defects in a‐Si:H by the deposition of the SiN overlayer. It was shown by Fourier transform infrared attenuated total reflection that the origin of the defects was hydrogen effusion from a‐Si:H.