Semiconductor device and manufacturing method therefor
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Hisashi Ohtani, Toshiji Hamatani
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Abstract
An active layer of an NTFT includes a channel forming region, at least a first impurity region, at least a second impurity region and at least a third impurity region therein. Concentrations of an impurity in each of the first, second and third impurity regions increase as distances from the channel forming region become longer. The first impurity region is formed to be overlapped with a side wall. A gate overlapping structure can be realized with the side wall functioning as an electrode.
Claims15
A method of manufacturing a semiconductor device, said method comprising the steps of:
- forming an active layer over an insulating surface;
- forming an insulating film on the active layer;
- forming a wiring over the active layer having the insulating film interposed therebetween;
- introducing an impurity selected from group 15 of the periodic table into the active layer using the wiring as a mask;
- forming at least a sidewall on a side portion of the wiring;
- introducing the impurity selected from group 15 of the periodic table into the active layer using the wiring and the sidewall as a mask;
- removing a portion of the insulating film to expose a portion of the active layer;
- and
- introducing the impurity selected from group 15 of the periodic table into the exposed portion of the active layer.
A method of manufacturing a semiconductor device, said method comprising the steps of:
- forming a first active layer and a second active layer over an insulating surface;
- forming an insulating film on each of the first active layer and the second active layer;
- forming a first wiring over the first active layer having the insulating film interposed therebetween and a second wiring over the second active layer having the insulating film interposed therebetween;
- introducing an impurity selected from group 15 of the periodic table into each of the first and second active layers using each of the first and second wirings as a mask;
- forming at least a sidewall on a side portion of each of the first and second wirings;
- introducing the impurity selected from group 15 of the periodic table into each of the first and second active layers using each of the first and second wirings and the sidewall as a mask;
- removing a first portion of the insulating film to expose a portion of the first active layer;
- introducing the impurity selected from group 15 of the periodic table into the exposed portion of the first active layer;
- removing a second portion of the insulating film to expose a portion of the second active layer;
- and
- introducing an impurity selected from group 13 of the periodic table into the exposed portion of the second active layer.
Dependencies are inferred from the claim text.