Electronic device and electronic apparatus
First Claim
Patent Images
1. An EL display device comprising:
- a first thin film transistor comprising;
at least two channel forming regions; and
an LDD (lightly-doped drain) region between the two channel forming regions wherein the LDD region partially overlaps a gate electrode of the first thin film transistor with a gate insulating film interposed therebetween;
a second thin film transistor electrically connected to the first thin film transistor, comprising;
a third channel region; and
an impurity region partially overlapping a gate electrode of the second thin film transistor with the gate insulating film interposed therebetween, andan EL element electrically connected to the second thin film transistor.
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Abstract
An EL display having high operating performance and reliability is provided. LDD regions 15a through 15d of a switching TFT 201 formed in a pixel are formed such that they do not overlap gate electrodes 19a and 19b to provide a structure which is primarily intended for the reduction of an off-current. An LDD region 22 of a current control TFT 202 is formed such that it partially overlaps a gate electrode 35 to provide a structure which is primarily intended for the prevention of hot carrier injection and the reduction of an off-current. Appropriate TFT structures are thus provided depending on required functions to improve operational performance and reliability.
103 Citations
24 Claims
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1. An EL display device comprising:
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a first thin film transistor comprising; at least two channel forming regions; and an LDD (lightly-doped drain) region between the two channel forming regions wherein the LDD region partially overlaps a gate electrode of the first thin film transistor with a gate insulating film interposed therebetween; a second thin film transistor electrically connected to the first thin film transistor, comprising; a third channel region; and an impurity region partially overlapping a gate electrode of the second thin film transistor with the gate insulating film interposed therebetween, and an EL element electrically connected to the second thin film transistor. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An EL display device comprising:
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a first thin film transistor comprising; at least two channel forming regions; and an LDD region between the two channel forming regions wherein the LDD region is formed in a region which does not overlap a gate electrode of the first thin film transistor; a second thin film transistor electrically connected to the first thin film transistor, comprising; a third channel region; and an impurity region partially overlapping a gate electrode of the second thin film transistor with a gate insulating film interposed therebetween, and an EL element electrically connected to the second thin film transistor. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An EL display device comprising:
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a first thin film transistor comprising; a first island-shaped semiconductor film; a gate insulating film formed over the first island-shaped semiconductor film; a first gate electrode formed over the first island-shaped semiconductor film with the gate insulating film interposed therebetween; and a second gate electrode formed over the first island-shaped semiconductor film with the gate insulating film interposed therebetween; a second thin film transistor electrically connected to the first thin film transistor, comprising; a second island-shaped semiconductor film; and a third gate electrode formed over the second island-shaped semiconductor film with the gate insulating film interposed therebetween; and an EL element electrically connected to the second thin film transistor, wherein the first island-shaped semiconductor film comprises; a first pair of LDD regions partially overlapping the first gate electrode with the gate insulating film interposed therebetween; a first channel forming region between the first pair of LDD regions and overlapping the first gate electrode with the gate insulating film interposed therebetween; a second pair of LDD regions partially overlapping the second gate electrode with the gate insulating film interposed therebetween; and a second channel forming region between the second pair of LDD regions and overlapping the second gate electrode with the gate insulating film interposed therebetween, and wherein the second island-shaped semiconductor film comprises; a third channel forming region overlapping the third gate electrode with the gate insulating film interposed therebetween; and an impurity region adjacent to the third channel forming region wherein the impurity region partially overlaps the third gate electrode with the gate insulating film interposed therebetween. - View Dependent Claims (14, 15, 16, 17, 18)
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19. An EL display device comprising:
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a first thin film transistor comprising; a first island-shaped semiconductor film; a gate insulating film formed over the first island-shaped semiconductor film; a first gate electrode formed over the first island-shaped semiconductor film with the gate insulating film interposed therebetween; and a second gate electrode formed over the first island-shaped semiconductor film with the gate insulating film interposed therebetween; a second thin film transistor electrically connected to the first thin film transistor, comprising; a second island-shaped semiconductor film; and a third gate electrode formed over the second island-shaped semiconductor film with the gate insulating film interposed therebetween; and an EL element electrically connected to the second thin film transistor, wherein the first island-shaped semiconductor film comprises; a first pair of LDD regions formed in a region which does not overlap with the first gate electrode; a first channel forming region between the first pair of LDD regions and overlapping the first gate electrode with the gate insulating film interposed therebetween; a second pair of LDD regions formed in a region which does not overlap the second gate electrode with the gate insulating film interposed therebetween, and a second channel forming region between the second pair of LDD regions and overlapping the second gate electrode with the gate insulating film interposed therebetween, and wherein the second island-shaped semiconductor film comprises; a third channel forming region overlapping the third gate electrode with the gate insulating film interposed therebetween; and an impurity region adjacent to the third channel forming region wherein the impurity region partially overlaps the third gate electrode with the gate insulating film interposed therebetween. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification