Deposition of silicon nitride thin films by hot-wire CVD at 100ºC and 250ºC

Abstract

Silicon nitride thin films for use as passivation layers in solar cells and organic electronics or as gate dielectrics in thin-film transistors were deposited by the Hot-wire chemical vapor deposition technique at a high deposition rate (1-3 Ǻ/s) and at low substrate temperature. Films were deposited using NH3/SiH4 flow rate ratios between 1 and 70 and substrate temperatures of 100º C and 250ºC. For NH3/SiH4 ratios between 40 and 70, highly transparent (T ~ 90%), dense films (2.56 - 2.74 g/cm3) with good dielectric properties and refractive index between 1.93 and 2.08 were deposited on glass substrates. Etch rates in BHF of 2.7 Ǻ/s and <0.5 Ǻ/s were obtained for films deposited at 100ºC and 250ºC, respectively. Films deposited at both substrate temperatures showed electrical conductivity ~ 10-14 Ω-1cm-1 and breakdown fields >10 MV cm−1.