Method of making a field effect transistor

Claim 1

A method of making an FET having a semiconductor substrate, a source, and a drain, the method comprising the steps of: (a) forming the source and the drain at respective locations on a surface of the semiconductor substrate; (b) forming a first insulation film on said surface of the semiconductor substrate and the source and the drain; (c) coating a photoresist on the first insulation film; (d) patterning the photoresist using a photolithography process to form a photoresist pattern, an edge portion of said photoresist pattern having sidewalls defining a first space, said first space exposing a portion of said first insulation film corresponding to a gate length between the source and the drain; (e) forming a second insulating film on said exposed portion of the first insulation film and the patterned photoresist including said sidewalls of said patterned photoresist; (f) etching the second insulation film to form sidewall insulation films at said sidewalls of the patterned photoresist defining the first space; (g) etching the first insulation film using the sidewall insulation films and the photoresist pattern as an etching mask to form first insulation film patterns, said first insulation film patterns forming a second space beneath the first space, the second space having a width smaller than a width of the first space; (h) removing the sidewall insulation films to form a T-shaped space; (i) depositing a conductive material to form a T-shaped gate in the T-shaped space, said conductive material also being deposited on said patterned photoresist; (j) removing the patterned photoresist and said conductive material deposited on the patterned photoresist after forming the T-shaped gate; and (k) removing the first insulation film patterns.

Claim 2

A method of making an FET having a semiconductor substrate, a source, and a drain, the method comprising the steps of: (a) forming the source and the drain at respective locations on a surface of the semiconductor substrate; (b) forming a first insulation film on said surface of the semiconductor substrate and the source and the drain; (c) coating a photoresist on the first insulation film; (d) patterning the photoresist using a photolithography process to form a photoresist pattern, an edge portion of said photoresist pattern having sidewalls defining a first space, said first space exposing a portion of said first insulation film corresponding to a gate length between the source and the drain; (e) forming a second insulating film on said exposed portion of the first insulation film and the patterned photoresist including said sidewalls of said patterned photoresist; (f) etching the second insulation film to form sidewall insulation films at said sidewalls of the patterned photoresist defining the first space; (g) etching the first insulation film using the sidewall insulation films and the photoresist pattern as an etching mask to form first insulation film patterns, said first insulation film patterns forming a second space beneath the first space, the second space having a width smaller than a width of the first space; (h) removing the sidewall insulation films to form a T-shaped space; (i) depositing a conductive material to form a T-shaped gate in the T-shaped space, said conductive material also being deposited on said patterned photoresist; (j) removing the patterned photoresist and said conductive material deposited on the patterned photoresist after forming the T-shaped gate; and (k) removing the first insulation film patterns.