US 6,087,205 A · Method of fabricating staggered thin film transistor with an improved ohmic contact structure

Abstract

A method of forming multi-layer structure of source/drain electrodes and an amorphous silicon layer in a forward staggered thin film transistor. Source/drain electrodes are selectively provided on an insulator. Each of the source/drain electrodes comprises an undoped transparent conductive film on the insulator and an impurity doped transparent conductive film on the insulator and an impurity doped transparent conductive film extending over the undoped transparent conductive film. An amorphous silicon active layer extends over the source/drain electrodes and a top surface of the insulator so that the amorphous silicon active layer over the source/drain electrodes has an impurity diffused interface in contact with the impurity doped transparent conductive film to form ohmic contacts between the impurity doped transparent conductive film and the amorphous silicon active layer. The amorphous silicon active layer in contact wit the top surface of the insulator between the source/drain electrodes is free of impurities.

Claims30

Dependent claims

A method of forming a multi-layer structure between source/drain electrodes and an amorphous silicon layer in a forward staggered thin film transistor, said method comprising the steps of:

forming an undoped indium tin oxide transparent conductive film on an insulator;
forming an impurity doped indium tin oxide transparent conductive film on said undoped transparent conductive film;
patterning laminations of said undoped transparent conductive film and said impurity doped transparent conductive film to form source/drain electrodes;
and
forming an amorphous silicon active layer over said source/drain electrodes and a top surface of said insulator along with a heat treatment so that in said amorphous silicon active layer over said source/drain electrodes, an impurity diffused interface is formed, which is in contact with said impurity doped transparent conductive film thereby to form ohmic contacts between said impurity doped transparent conductive film and said amorphous silicon active layer, whilst no impurity introduced region is formed in said amorphous silicon active layer being in contact with said top surface of said insulator and being positioned between said source/drain electrodes.

2 more elements

A method of forming a forward staggered thin film transistor, said method comprising the steps of:

forming an undoped indium tin oxide transparent conductive film on an insulator;
forming an n type impurity doped indium tin oxide transparent conductive film on said undoped transparent conductive film;
patterning laminations of said undoped transparent conductive film and said impurity doped transparent conductive film to form source/drain electrodes;
and
successively forming an amorphous silicon active layer and a gate insulation film over said source/drain electrodes and a top surface of said insulator along with a heat treatment so that in said amorphous silicon active layer over said source/drain electrodes, an impurity diffused interface is formed which is in contact with said impurity doped transparent conductive film thereby to form ohmic contacts between said impurity doped transparent conductive film and said amorphous silicon active layer, whilst no impurity introduced region is formed in said amorphous silicon active layer being in contact with said top surface of said insulator and being positioned between said source/drain electrodes;
forming a gate electrode film on said gate insulation film;
and
patterning laminations of said amorphous silicon active layer, said gate insulation film and said gate electrode film.

5 more elements

A method of forming a forward staggered thin film transistor, said method comprising the steps of:

selectively forming an optical shielding metal film on a first region of a top surface of a glass substrate;
forming an inter-layer insulator which extends over said optical shielding metal film and said top surface of said glass substrate;
forming an undoped indium tin oxide film on said inter-layer insulator;
forming an impurity doped indium tin oxide film on said undoped indium tin oxide film;
patterning laminations of said undoped indium tin oxide film and said impurity doped indium tin oxide film to form source/drain electrodes;
and
successively forming an amorphous silicon active layer and a gate insulation film over said source/drain electrodes and a top surface of said insulator along with a plasma chemical vapor deposition method so that in said amorphous silicon active layer over said source/drain electrodes, an impurity diffused interface is formed which is in contact with said impurity doped indium tin oxide film thereby to form ohmic contacts between said impurity doped indium tin oxide film and said amorphous silicon active layer, whilst no impurity introduced region is formed in said amorphous silicon active layer being in contact with said top surface of said insulator and being positioned between said source/drain electrodes;
forming a gate electrode film on said gate insulation film;
and
patterning laminations of said amorphous silicon active layer, said gate insulation film and said gate electrode film.

7 more elements

Dependencies are inferred from the claim text.

Method of fabricating staggered thin film transistor with an improved ohmic contact structure

Life of this patent

Method of fabricating staggered thin film transistor with an improved ohmic contact structure

Life of this patent

Abstract

Claims30