An in-line mass spectrometer, and Langmuir probes, were used to study the plasma-immersion H passivation of grain-boundary defects in polycrystalline thin-film transistors. The relative fluxes of H+ and H2+, as well as the total ion-current density, were measured at the substrate location in an electron cyclotron resonance H discharge. Measurements were made within the range of operating conditions where passivation rates were known to vary widely. The resultant data exhibited a strong correlation of both H+ flux and ion bombardment energy, with good transistor performance being obtained at operating pressures below 0.001Torr. It was suggested that discharge operating conditions which promoted the dissociation of H2 to form H and H+ (which could diffuse more rapidly through the solid material than did H2) were important.

E.S.Cielaszyk, K.H.R.Kirmse, R.A.Stewart, A.E.Wendt: Applied Physics Letters, 1995, 67[21], 3099-101