Semiconductor device and manufacturing method thereof

A method of manufacturing a semiconductor device, comprising:

• forming a gate wiring over an insulating surface;
• forming an insulating film covering the insulating surface and the gate wiring;
• forming a first amorphous semiconductor film over the insulating film;
• forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
• forming a metal film over the second amorphous semiconductor film;
• etching the metal film, the second amorphous semiconductor film, the first amorphous semiconductor film and the insulating film continuously to form a side edge of the first amorphous semiconductor film into a taper shape;
• forming a transparent conductive film in contact with the metal film;
• and
• etching the transparent conductive film, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film to expose a part of the first amorphous semiconductor film, to form a pixel electrode from the transparent conductive film, to form a source wiring from the metal film and to form a source region and a drain region from the second amorphous semiconductor film.

A method of manufacturing a semiconductor device, comprising:

• forming a gate wiring over an insulating surface;
• forming an insulating film over the insulating surface and the gate wiring;
• forming a first amorphous semiconductor film over the insulating film;
• forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
• forming one of an aluminum film and a titanium film over the second amorphous semiconductor film;
• etching the one of the aluminum film and the titanium film, the second amorphous semiconductor film and the first amorphous semiconductor film continuously to form a side edge of the first amorphous semiconductor film into a taper shape;
• forming a transparent conductive film in contact with the one of the aluminum film and the titanium film;
• and
• etching the transparent conductive film, the one of the aluminum film and the titanium film and the second amorphous semiconductor film to form a pixel electrode, a source wiring, a source region and a drain region,
• wherein the first amorphous semiconductor film is etched into the taper shape with a mixture gas of Cl2 and BCl2.

A method of manufacturing a semiconductor device, comprising:

• forming a gate wiring over an insulating surface;
• forming an insulating film over the insulating surface and the gate wiring;
• forming a first amorphous semiconductor film over the insulating film;
• forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
• forming a tantalum film over the second amorphous semiconductor film;
• etching the tantalum film, the second amorphous semiconductor film and the first amorphous semiconductor film continuously to form a side edge of the first amorphous semiconductor film into a taper shape;
• forming a transparent conductive film in contact with the tantalum film;
• and
• etching the transparent conductive film, the tantalum film and the second amorphous semiconductor film to form a pixel electrode, a source wiring, a source region and a drain region,
• wherein the first amorphous semiconductor film is etched into the taper shape with a mixture gas of Cl2 and CF4.

A method of manufacturing a semiconductor device, comprising:

• forming a gate wiring over an insulating surface;
• forming an insulating film over the insulating surface and the gate wiring;
• forming a first amorphous semiconductor film over the insulating film;
• forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
• forming a tungsten film over the second amorphous semiconductor film;
• etching the tungsten film, the second amorphous semiconductor film and the first amorphous semiconductor film continuously to form a side edge of the first amorphous semiconductor film into a taper shape;
• forming a transparent conductive film in contact with the tungsten film;
• and
• etching the transparent conductive film, the tungsten film and the second amorphous semiconductor film to form a pixel electrode, a source wiring, a source region and a drain region,
• wherein the first amorphous semiconductor film is etched into the taper shape with one of a mixture gas of Cl2, CF4 and O2 and a mixture gas of Cl2, SF6 and O2.

A method of manufacturing a semiconductor device, comprising:

• forming a gate wiring over an insulating surface;
• forming an insulating film covering the insulating surface and the gate wiring;
• forming a first amorphous semiconductor film over the insulating film;
• forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
• forming a metal film over the second amorphous semiconductor film;
• etching the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film without changing an etching gas to form a side edge of the first amorphous semiconductor film into a taper shape;
• forming a transparent conductive film in contact with the metal film;
• and
• etching the transparent conductive film, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film to expose a part of the first amorphous semiconductor film, to form a pixel electrode from the transparent conductive film, to form a source wiring from the metal film and to form a source region and a drain region from the second amorphous semiconductor film.

A method of manufacturing a semiconductor device, comprising:

• forming a gate wiring over an insulating surface;
• forming an insulating film covering the insulating surface and the gate wiring;
• forming a first amorphous semiconductor film over the insulating film;
• forming a second amorphous semiconductor film containing an impurity element of one conductivity type over the first amorphous semiconductor film;
• forming a metal film over the second amorphous semiconductor film;
• etching the metal film, the second amorphous semiconductor film, the first amorphous semiconductor film and the insulating film without changing an etching gas to form a side edge of the first amorphous semiconductor film into a taper shape;
• forming a transparent conductive film in contact with the metal film;
• and
• etching the transparent conductive film, the metal film, the second amorphous semiconductor film and the first amorphous semiconductor film to expose a part of the first amorphous semiconductor film, to form a pixel electrode from the transparent conductive film, to form a source wiring from the metal film and to form a source region and a drain region from the second amorphous semiconductor film.