1. A semiconductor device comprising:
a first conductivity type first diffusion layer located in a semiconductor layer;
a gate electrode located over the first diffusion layer and the semiconductor layer via a gate insulation film;
a second conductivity type second diffusion layer that is one of a source region and a drain region, and is located in the first diffusion layer to one side of the gate electrode in a channel length direction;
a second conductivity type third diffusion layer that is the other of the source region and the drain region, and is located in the semiconductor layer to the other side of the gate electrode in the channel length direction;
a plurality of first conductivity type fourth diffusion layers that are located in the second diffusion layer and are electrically connected to the first diffusion layer;
an insulation film that is located over the semiconductor layer, the first diffusion layer, and the gate electrode;
a plurality of first contact holes that are located in the insulation film, and are located over the second diffusion layer and the fourth diffusion layer; and
a plurality of second contact holes that are located in the insulation film, and are located over the third diffusion layer,
wherein the plurality of fourth diffusion layers are located along the gate electrode, and each of the plurality of fourth diffusion layers is surrounded by the second diffusion layer,
the plurality of first contact holes are located along the gate electrode,
the plurality of second contact holes are located along the gate electrode, and
a pitch of the plurality of fourth diffusion layers is larger than a pitch of the plurality of first contact holes.
2. The semiconductor device according to claim 1,
wherein the plurality of fourth diffusion layers are located in a line along the gate electrode,
the plurality of first contact holes are located in a line along the gate electrode,
the plurality of second contact holes are located in a line along the gate electrode, and
the pitch of the plurality of first contact holes is the same as the pitch of the plurality of second contact holes.
3. The semiconductor device according to claim 1, wherein the plurality of first contact holes include a contact hole that overlaps with the second diffusion layer and does not overlap with the fourth diffusion layer, and a contact hole that overlaps with the fourth diffusion layer and does not overlap with the second diffusion layer.
4. The semiconductor device according to claim 3, wherein the plurality of first contact holes include a contact hole that overlaps with the second diffusion layer and the fourth diffusion layer.
5. The semiconductor device according to claim 3, wherein at least one of the plurality of fourth diffusion layers does not overlap with any of the plurality of first contact holes.
6. The semiconductor device according to claim 1, wherein the plurality of first contact holes include a contact hole that establishes contact with the second diffusion layer and a contact hole that establishes contact with the fourth diffusion layer.
7. The semiconductor device according to claim 6, wherein the plurality of first contact holes include a contact hole that establishes contact with both the second diffusion layer and one of the fourth diffusion layers.
8. The semiconductor device according to claim 6, wherein at least one of the plurality of fourth diffusion layers does not have contact with any of the plurality of first contact holes.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for inhibiting corrosion of a metallic substance in an aqueous cooling water system containing soluble SiO2 of greater than 10 mgL wherein said aqueous system derives water from make-up source water, comprising the steps:
a) removing hardness ions from said source water;
b) controlling the ionic strength of the aqueous system water such that said aqueous system water possesses a measurable conductivity of at least 1 \u03bcmhos;
c) elevating and maintaining the pH of said aqueous system water such that said aqueous system water possesses a pH of approximately 9.0 or greater; and
d) cyclically contacting said aqueous system water with said metallic substance, wherein said pH and ionic strength increases the amount of soluble silica in the multimeric form present in said aqueous system water and inhibits corrosion of said metallic substance.
2. The method of claim 1 wherein in step a), said hardness ions comprise ions of calcium and magnesium.
3. The method of claim 1 wherein said aqueous system water contains soluble SiO2 residual that is between 10 mgL to 200 mgL.
4. The method of claim 2 wherein in step a), said hardness ions are removed in amounts equal to or less than approximately 20% of the SiO2 present within said source water.
5. The method of claim 2 wherein in step a), said hardness ions are removed in amounts equal to or less than approximately 5% of the SiO2 present within said source water.
6. The method of claim 1 wherein in step c), said pH is maintained at 9.6 or higher.
7. The method of claim 1 wherein in step a), said hardness ions are removed via a method selected from the group consisting of ion exchange, selective ion removal with reverse osmosis, reverse osmosis, electro chemical removal, chemical precipitation, evaporation and distillation.
8. The method of claim 1 wherein in step c), said pH is elevated by adding an alkaline agent.
9. The method of claim 8 wherein said alkali agent comprises sodium hydroxide.
10. The method of claim 1 wherein in step c), said pH is elevated by evaporating a portion of said aqueous system water.
11. The method of claim 1 wherein in step c), said pH is elevated by distilling a portion of said aqueous system water.
12. The method of claim 1 wherein said metallic substance is selected from the group consisting of carbon steel, copper, copper alloy and stainless steel alloy.
13. The method of claim 1 wherein prior to step a), said methods of the present invention comprises the step:
a) analyzing said source water to determine the concentration of SiO2 present therein.
14. The method of claim 1 wherein in step b), said ionic strength of said aqueous system water is controlled such that said aqueous system water possesses a conductivity of at least 500 \u03bcmhos.
15. The method of claim 1 wherein said aqueous system water contains soluble SiO2 of at least 200 mgL.