| 摘要 |
PURPOSE:To make a gate insulating film thin and reduce a threshold voltage, by spreading a semiconductor island more than a conventional one and leaving a source, drain and gate electrodes and the lower part of the entire wiring continuous thereto in an island shape. CONSTITUTION:A semiconductor thin film is formed on an insulating substrate 1, a conventional semiconductor island, a source, drain and gate electrodes and a part slightly larger than a region including a lead-out wiring are left as a new semiconductor island 2, other parts are removed by an etching, and next a gate insulating film 3 is formed. Then, oxygen or nitrogen is ion-implanted into parts 2' except for the operating region of the semiconductor film island being insulated. The ion implantation thereat is performed in several times by varying acceleration voltages, and thus the semiconductor film is perfectly insulated from up to low. |
