Light emitting device and manufacturing method thereof
First Claim
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1. A light emitting device comprising an n-channel TFT and a light emitting element in each of pixels, the n-channel TFT comprising:
- an active layer including;
a channel forming region;
an n-type impurity region (c) adjacent to the channel forming region;
an n-type impurity region (b) adjacent to the n-type impurity region (c); and
an n-type impurity region (a) adjacent to the n-type impurity region (b);
a gate insulating layer provided over the active layer; and
a gate electrode provided over the gate insulating layer including;
a first gate electrode provided over the gate insulating layer; and
a second gate electrode provided over the first gate, wherein the first gate electrode overlaps the channel forming region and the n-type impurity region (c) with the gate insulating layer therebetween, and wherein the second gate electrode overlaps the channel forming region with the gate insulating layer therebetween.
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Abstract
The light emitting device according to the present invention is characterized in that a gate electrode comprising a plurality of conductive films is formed, and concentrations of impurity regions in an active layer are adjusted with making use of selectivity of the conductive films in etching and using them as masks. The present invention reduces the number of photolithography steps in relation to manufacturing the TFT for improving yield of the light emitting device and shortening manufacturing term thereof, by which a light emitting device and an electronic appliance are inexpensively provided.
325 Citations
24 Claims
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1. A light emitting device comprising an n-channel TFT and a light emitting element in each of pixels, the n-channel TFT comprising:
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an active layer including;
a channel forming region;
an n-type impurity region (c) adjacent to the channel forming region;
an n-type impurity region (b) adjacent to the n-type impurity region (c); and
an n-type impurity region (a) adjacent to the n-type impurity region (b);
a gate insulating layer provided over the active layer; and
a gate electrode provided over the gate insulating layer including;
a first gate electrode provided over the gate insulating layer; and
a second gate electrode provided over the first gate, wherein the first gate electrode overlaps the channel forming region and the n-type impurity region (c) with the gate insulating layer therebetween, and wherein the second gate electrode overlaps the channel forming region with the gate insulating layer therebetween. - View Dependent Claims (3, 5, 7, 9, 11, 13)
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2. A light emitting device comprising a driver circuit comprising a n-channel TFT, and pixel portion comprising a light emitting element, the n-channel TFT comprising:
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an active layer including;
a channel forming region;
an n-type impurity region (c) adjacent to the channel forming region;
an n-type impurity region (b) adjacent to the n-type impurity region (c); and
an n-type impurity region (a) adjacent to the n-type impurity region (b);
a gate insulating layer provided over the active layer; and
a gate electrode provided over the gate insulating layer including;
a first gate electrode provided over the gate insulating layer; and
a second gate electrode provided over the first gate, wherein the first gate electrode overlaps the channel forming region and the n-type impurity region (c) with the gate insulating layer therebetween, and wherein the second gate electrode overlaps the channel forming region with the gate insulating layer therebetween. - View Dependent Claims (4, 6, 8, 10, 12, 14)
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15. A method of manufacturing a light emitting device comprising:
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a first step of forming a semiconductor film on a insulating material;
a second step of forming an insulating film covering the semiconductor film;
a third step of forming a conductive film on the insulation film by laminating two or more conductive layers;
a fourth step of forming a gate electrode by etching the conductive film;
a fifth step of adding an n-type impurity element to the semiconductor film using the gate electrode as a mask;
a sixth step of etching a side face of the gate electrode before selectively etching a first portion of the gate electrode;
a seventh step of adding an n-type impurity element to the semiconductor film after the sixth step through a second part of the gate electrode using the gate electrode except the second portion as a mask;
a eighth step of forming an insulating film covering the gate electrode;
a ninth step of forming wirings on the insulating film formed in the eighth step to be in contact with the semiconductor film; and
a tenth step of forming a light emitting element on the insulating film formed in the eighth step. - View Dependent Claims (16, 17, 18, 23)
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19. A method of manufacturing a light emitting device comprising:
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a first step of forming a semiconductor film on a insulating material;
a second step of forming an insulating film covering the semiconductor film;
a third step of forming a conductive film on the insulation film by laminating a first conductive film and a second conductive film;
a fourth step of forming a gate electrode which comprises a first gate electrode comprising the first conductive film and a second gate electrode comprising the second conductive film by etching the conductive film;
a fifth step of adding an n-type impurity element to the semiconductor film using the first gate electrode and the second gate electrode as a mask;
a sixth step of etching the first gate electrode and the second gate electrode before selectively etching the second gate electrode;
a seventh step of adding an n-type impurity element to the semiconductor film after the sixth step through a part of the first gate electrode using the selectively etched second gate electrode as a mask;
a eighth step of forming an insulating film covering the gate electrode;
a ninth step of forming wirings on the insulating film formed in the eighth step to be in contact with the semiconductor film; and
a tenth step of forming a light emitting element on the insulating film formed in the eighth step. - View Dependent Claims (20, 21, 22, 24)
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Specification
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Current AssigneeSemiconductor Energy Laboratory Co., Ltd.
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Original AssigneeSemiconductor Energy Laboratory Co., Ltd.
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InventorsFukunaga, Takeshi, Koyama, Jun, Yamazaki, Shunpei, Inukai, Kazutaka
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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current438/151
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CPC Class CodesH01L 27/1214 comprising a plurality of T...H01L 27/1259 Multistep manufacturing met...H01L 27/127 with a particular formation...H10K 59/12 Active-matrix OLED [AMOLED]...
