| 摘要 |
<p>PURPOSE:To manufacture a thin film transistor operating at a low voltage without causing a shift of a threshold value, by a method wherein a gate insulation film of the thin film transistor is made to have a superlattice structure prepared by laminating several tens of laminates of an insulating material having a large band gap and an insulating material having a large dielectric constant. CONSTITUTION:A gate insulation film 3 is an insulating film having a superlattice structure which is prepared by laminating twenty laminates of SiO2 20 Angstrom thick and Ta2O5 50 Angstrom thick. Due to a quantum size effect of this superlattice structure, a conductor energy level Ec of Ta2O5 rises in every cycle, a threshold value turns larger than the one of Ta2O5, and thereby a shift of the threshold value due to the implantation of hot electrons is prevented. Besides, the dielectric constant of this gate insulation film is larger than 3.9 of SiO2, thus enabling the operation of a switch at a low voltage.</p> |
