| 摘要 |
PURPOSE:To sufficiently reduce the threshold voltage and the gate voltage required for action, and to extremely increase the efffective mobility by a method wherein a plasma Si nitride film is formed above an active layer where a channel is formed, and is then annealed. CONSTITUTION:A polycrystalline Si film 2, a gate oxide film 3 made of an SiO2 film, a gate electrode 4 made of an impurity-doped polycrystalline Si film, and a PSG film 5 are formed on a quartz substrate 1. The phosphorus in the PSG film 5 is thermally diffused by heat treatment, resulting in the formation of a source region 6 and a drain region 7 made of n<+> layers. The polycrystalline Si film 2a between the source and drain constitutes the active layer 8. Al lead-out electrodes 9 and 10 are formed. An Si nitride film 11 is coat-formed by the plasma CVD method with the mixed gas of SiH4 and NH3 and then annealed. As the annealing time is prolonged, the threshold voltage and the gate voltage required for MOSFET action reduce and the effective mobility becomes much larger. |
