A method of fabricating a thin film transistor (TFT) includes the steps of forming a gate conductor on a substrate; depositing a gate dielectric layer of silicon nitride over the gate conductor; treating the exposed silicon nitride on the surface of the gate dielectric layer with a hydrogen plasma at a power level of at least 44 mW/cm.sup.2 for at least 5 minutes; depositing a layer of amorphous silicon semiconductor material over the gate dielectric layer; depositing a layer of n+ doped silicon over the treated amorphous silicon surface; depositing a layer of source/drain metallization over the n+ doped layer; and patterning the source/drain metallization and portions of the underlying n+ doped layer to form source and drain electrodes. The deposition of the TFT material layers and the hydrogen plasma treatment is preferably by plasma enhanced chemical vapor deposition.