| 摘要 |
PURPOSE:To increase gate capacitance by using a film having a dielectric constant larger than Si3N4 as an insulating layer for a thin-film FET and making N concentration in the vicinity of the interface on the nonsingular crystal semiconductor layer side higher than the gate electrode side. CONSTITUTION:A gate electrode 11 in Cr is formed onto an insulating substrate 10, a TaxAlyO layer 12 containing no N is deposited in Ar, N2 is introduced into Ar as the layer 12 is left as it is, a TaxAlyO layer 13 containing N in high concentration is deposited, thus shaping the concentration gradient of N increasing to the surface of the layer 13 from the gate electrode 11 side. The TaxAlyO 13 containing N in high concentration has dense structure, and is not damaged on the deposition of amorphous Si through a CVD plasma method, and the state of the interface is kept excellent. A source electrode 16 and a drain electrode in Al are attached, thus completing the titled transistor. When the FET according to he constitution is compared to the case when Si3N4 in the same film thickness is used as a gate insulating film, ON currents are trebled approximately, interelectrode short circuits are also reduced, and characteristics are stabilized for a prolonged term. A film in which Ta2O3 is superposed on Si3N4 is also effective. |
