Insulated gate field effect transistor and a method of manufacturing the same
Disclosed herein is an insulated gate field effect transistor including: (A) a source/drain region and a channel formation region; (B) a gate electrode formed above the channel formation region; and (C) a gate insulating film; wherein the gate insulating film is composed of a gate insulating film main body portion formed between the gate electrode and the channel formation region, and a gate insulating film extension portion extending from the insulating film main body portion to a middle of a side surface portion of the gate electrode, and when a height of the gate electrode is H Gate and a height of the gate insulating film extension portion is H Ins with a surface of the channel formation region as a reference, a relationship of H Ins <H Gate is fulfilled.
1. An insulated gate field effect transistor comprising:
(A) a source/drain region and a channel formation region;
(B) a gate electrode formed above said channel formation region;
(C) sidewall spacers between which said gate electrode is located; and
(D) a gate insulating film;
wherein,
said gate electrode is composed of a first layer made of a first metallic material, a second layer made of a second metallic material different from the first metallic material, and a third layer made of a third metallic material different from the first metallic material,
said first layer extends from a bottom surface portion of said gate electrode facing said channel formation region to a height H Mt-1 along said side surface of said gate electrode,
said second layer and said third layer occupy a remaining portion of said gate electrode in a lamination state.
a height of an interface between said second layer and said third layer is H Mt-2 with said surface of said channel formation region as the reference,
H Mt-1 <H Gate , and H mt-1 ≈H Mt-2 ,
said gate insulating film is composed of a gate insulating film main body portion formed between said gate electrode and said channel formation region, and gate insulating film extension portion extending from said insulating film main body portion along side surface of said gate electrode,
a height of said gate electrode is H Gate and a height of said gate insulating film extension portion is H Ins with a surface of said channel formation region as a reference,
K Ins <H Gate , and
above H Ins said gate electrode extends out to said sidewall spacers.
2. The insulated gate field effect transistor according to claim 1 , wherein:
said gate electrode is composed of a first layer made of a first metallic material, and a second layer made of a second metallic material different from the first metallic material;
said first layer is formed so as to extend from a bottom surface portion of said gate electrode facing said channel formation region to a height H Mt-1 along said side surface of said gate electrode;
said second layer occupies a remaining portion of said gate electrode; and
H Mt-1 <H Gate .
3. The insulated gate field effect transistor according to claim 2 , further comprising:
a contact plug connected to a top surface of said gate electrode,
wherein,
said second layer exists between a bottom surface of said contact plug and an upper end portion of said gate insulating film extension portion.
4. The insulated gate field effect transistor according to claim 2 , wherein:
said second layer is composed of two layers having an outer layer and an inner layer;
said outer layer of said second layer extends from a surface of said first layer along said side surface of said gate electrode; and
said inner layer of said second layer occupies a remaining portion of said gate electrode.
5. The insulated gate field effect transistor according to claim 4 , further comprising:
a contact plug connected to a top surface of said gate electrode,
wherein,
at least one of said inner layer and said outer layer exists between a bottom surface of said contact plug and an upper end portion of said gate insulating film extension portion.
6. The insulated gate field effect transistor according to claim 1 , further comprising:
a contact plug connected to a top surface of said gate electrode,
wherein,
said third layer exists between a bottom surface of said contact plug and an upper end portion of said gate insulating film extension portion.
7. The insulated gate field effect transistor according to claim 1 , wherein 0.1≦H Ins /H Gate ≦0.95, and (H Gate −H Ins ) ≧5 nm.
8. The insulated gate field effect transistor according to claim 1 , wherein:
H Ins ≈H Mt-1 ≈H Mt-2 .
9. An insulated gate field effect transistor comprising:
(A) a source/drain region and a channel formation region;
(B) a gate electrode formed above said channel formation region;
(C) sidewalls between which the gate electrode is located; and
(D) a gate insulating film;
wherein,
said gate electrode is composed of a first layer made of a first metallic material, a second layer made of a second metallic material different from the first metallic material, and a third layer made of a third metallic material different from the first metallic material,
said first layer extends from a bottom surface portion of said gate electrode facing said channel formation region to a height H Mt-1 along said side surface of said gate electrode,
said second layer and said third layer occupy a remaining portion of said gate electrode in a lamination state;
a height of an interface between said second layer and said third layer is H M-2 with said surface of said channel formation region as the reference,
said gate insulating film is composed of a gate insulating film main body portion formed between said gate electrode and said channel formation region, and a gate insulating film extension portion extending from said insulating film main body portion to a top surface of said gate electrode, said gate insulating film defining a volume,
said gate insulating film is between said gate electrode and a top surface of said channel formation region and between said gate electrode and said sidewall spacers,
said gate electrode is composed of a first layer made of a first metallic material, a second layer made of a second metallic material different from the first metallic material, and a third layer made of a third metallic material different from the first metallic material,
said first layer extends from a bottom surface of said gate electrode facing said channel formation region to a height H Mt-1 along side surfaces of said gate insulating layer extension,
said first layer and said second layer occupy said volume defined by said gate insulating film,
said second layer and said third layer occupy a remaining portion of said gate electrode in a lamination state,
a height of said gate electrode is H Gate ,
a height of an interface between said second layer and said third layer is H Mt-2 with a surface of said channel formation region as a reference,
said interface extends across said entire gate electrode, and
H Mt-1 <H Gate , H Mt-2 <H Gate , and H Ins ≈H Mt-1 ≈H Mt-2 .
10. The insulated gate field effect transistor according to claim 9 , further comprising:
a contact plug connected to a top surface of said gate electrode,
wherein,
said third layer exists between a bottom surface of said contact plug and an upper end portion of said first layer.
11. The insulated gate field effect transistor according to claim 9 , wherein 0.1≦H Mt-1 /H Gate ≦0.95 and (H Gate −H Mt-1 ) ≧5 nm.