| 摘要 |
<p>PURPOSE:To increase component density, to facilitate manufacture and to improve reliability by constructing a thin film transistor in lamination on a thin film transistor for a memory and further by making an upper gate insulation film be a laminated film of a lower layer insulation film and others. CONSTITUTION:An upper gate insulation film 16 laid between a semiconductor layer 14 on an insulative substrate 11 and an upper gate electrode G20 is made to be a laminated film constructed of a lower layer insulation film 16a covering the whole of the layer 14, an insulating film 16b for an etching stopper formed on the whole of the surface of the film 16a and an upper layer insulation film 16c. Besides, the film thickness of the film 16 is made large on the part of the layer 14 corresponding to a memory area. Therefore, insulative separation can be attained between the region of a thin film transistor TrT20 for selection in the layer 14 and a lower gate electrode G10 of a thin film TrT10 for a memory and between the region of the TrT20 and the electrode G20. By constructing the TrT20 in lamination on the TrT10, accordingly, component density is increased by lessening an element area, easy manufacture of the memory is enabled by a reduced number of processes and, in addition, writing, erasure and reading can be executed stably. Besides, it is possible to form the film 16 with an excellent yield and thereby to improve reliability.</p> |
