THIN-FILM TRANSISTOR AND MANUFACTURING METHOD THEREOF
First Claim
1. A thin-film transistor comprising:
- a non-single-crystal semiconductor thin film formed on an insulating substrate;
a gate insulating film formed on the non-single-crystal semiconductor thin film;
a gate electrode formed on the gate insulating film and including a lower gate electrode and an upper gate electrode; and
a Lightly Doped Drain structure including a heavily doped region and a lightly doped region formed in the non-single-crystal semiconductor thin film;
wherein a difference in impurity concentration between the lightly doped region and the heavily doped region is equivalent to a concentration of an impurity blocked by the lower gate electrode from being introduced; and
the gate electrode does not exist over the lightly doped region.
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Accused Products
Abstract
A method for forming a thin-film transistor on an insulating substrate includes the steps of: forming a non-single-crystal semiconductor thin film on the insulating substrate; forming a gate insulating film on the non-single-crystal semiconductor thin film; forming a gate electrode including a lower gate electrode and an upper gate electrode on the gate insulating film, the lower gate electrode having a portion that is not covered by the upper gate electrode; forming a source-drain region and an LDD (lightly doped drain) region in the non-single-crystal thin film semiconductor film at a time by introducing an impurity into the non-single-crystal semiconductor thin film through the gate electrode and the gate insulating film; and etching away an exposed portion of the lower gate electrode by using the upper gate electrode as a mask.
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Citations
10 Claims
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1. A thin-film transistor comprising:
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a non-single-crystal semiconductor thin film formed on an insulating substrate; a gate insulating film formed on the non-single-crystal semiconductor thin film; a gate electrode formed on the gate insulating film and including a lower gate electrode and an upper gate electrode; and a Lightly Doped Drain structure including a heavily doped region and a lightly doped region formed in the non-single-crystal semiconductor thin film; wherein a difference in impurity concentration between the lightly doped region and the heavily doped region is equivalent to a concentration of an impurity blocked by the lower gate electrode from being introduced; and the gate electrode does not exist over the lightly doped region. - View Dependent Claims (2, 3, 10)
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4. A method for manufacturing a thin-film transistor, comprising the steps of:
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forming a non-single-crystal semiconductor thin film on an insulating substrate; forming a gate insulating film on the non-single-crystal semiconductor thin film; forming a gate electrode including a lower gate electrode and an upper gate electrode on the gate insulating film, the lower gate electrode having a portion that is not covered by the upper gate electrode; forming a heavily doped region and a lightly doped region in the non-single-crystal semiconductor thin film at a time by introducing an impurity into the non-single-crystal semiconductor thin film through the gate electrode and the gate insulating film; and etching away an exposed portion of the lower gate electrode by using the upper gate electrode as a mask. - View Dependent Claims (5, 6, 7, 8, 9)
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Specification