Method of making thin film transistors
First Claim
1. A method of making a thin film transistor comprising the steps of:
- forming a gate electrode on an insulating transparent substrate;
forming a first insulating layer, an amorphous silicon layer and a second insulating layer in turn on the gate electrode and the insulting transparent substrate;
coating a photoresist over the second insulating layer and performing a back substrate exposure using the gate electrode as a photo shield mask to form a photoresist pattern;
baking the photoresist pattern to flow outwardly so that it has a width approximately equal to a length of the gate electrode in order to prevent a channel overlap;
etching the second insulating layer using the baked photoresist pattern as a mask to form a second insulating layer pattern serving as a channel passivation layer;
removing thee photoresist pattern from the second insulating layer pattern;
forming an impurity-doped amorphous silicon layer in the amorphous silicon layer at opposite sides of the second insulating layer pattern;
depositing a refractory metal layer on the second insulating layer pattern and the impurity-doped amorphous silicon layer and consequently forming a silicide layer between the impurity-doped amorphous silicon layer and the refractory metal layer; and
patterning the refractory metal layer to form refractory metal layer patterns at opposite sides of the second insulating layer pattern to serve as a source electrode and a drain electrode.
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Abstract
A method of making thin film transistors, capable of reducing the extent of channel overlap between a gate electrode and source/drain regions, thereby achieving an improvement in signal-to-noise ratio. The method uses a impurity ion doping process and a process for forming a silicide layer using a refractory metal, so as to form source and drain electrodes in a self-aligned manner, with respect to the gate electrode. In order to avoid a channel overlap from occurring between the gate electrode and the source and drain electrodes, a photoresist pattern is subjected to a baking, which photoresist pattern defines an insulating layer pattern serving as a channel passivation layer to determine the of a channel region and the widths of source and drain regions. By the baking, the photoresist pattern flows outwardly so that its width is approximately equal to the length of the gate electrode.
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Citations
12 Claims
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1. A method of making a thin film transistor comprising the steps of:
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forming a gate electrode on an insulating transparent substrate; forming a first insulating layer, an amorphous silicon layer and a second insulating layer in turn on the gate electrode and the insulting transparent substrate; coating a photoresist over the second insulating layer and performing a back substrate exposure using the gate electrode as a photo shield mask to form a photoresist pattern; baking the photoresist pattern to flow outwardly so that it has a width approximately equal to a length of the gate electrode in order to prevent a channel overlap; etching the second insulating layer using the baked photoresist pattern as a mask to form a second insulating layer pattern serving as a channel passivation layer; removing thee photoresist pattern from the second insulating layer pattern; forming an impurity-doped amorphous silicon layer in the amorphous silicon layer at opposite sides of the second insulating layer pattern; depositing a refractory metal layer on the second insulating layer pattern and the impurity-doped amorphous silicon layer and consequently forming a silicide layer between the impurity-doped amorphous silicon layer and the refractory metal layer; and patterning the refractory metal layer to form refractory metal layer patterns at opposite sides of the second insulating layer pattern to serve as a source electrode and a drain electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of making a thin film transistor comprising the steps of:
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forming a gate electrode on an insulating transparent substrate; forming a first insulating layer, a polycrystalline silicon layer and a second insulating layer in turn on the gate electrode and the insulating transparent substrate; coating a photoresist over the second insulating layer and performing a back substrate exposure using the gate electrode as a photo shield mask to form a photoresist pattern; baking the photoresist pattern to flow outwardly so that it has a width approximately equal to a length of the gate electrode in order to prevent a channel overlap; etching the second insulating layer using the baked photoresist pattern as a mask to form a second insulating layer pattern serving as a channel passivation layer; removing the photoresist pattern from the second insulating pattern; forming an impurity-doped polycrystalline silicon layer in the polycrystalline silicon layer at opposite sides of the second insulating layer pattern; depositing a refractory metal layer on the second insulating layer pattern and the impurity-doped polycrystalline silicon layer and consequently forming a silicide layer between the impurity-doped polycrystalline silicon layer and the refractory metal layer; and patterning the refractory metal layer to form refractory metal layer patterns at opposite sides of the second insulating layer pattern to serve as a source electrode and a drain electrode.
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Specification