1. A nonvolatile semiconductor memory device comprising a memory cell, the memory cell comprising:
a first conductivity type well in a silicon substrate;
a second conductivity type semiconductor region having at least a pair of a first semiconductor region and a second semiconductor region, the second conductivity type semiconductor region being formed in the first conductivity type well;
a first gate insulating layer formed in the silicon substrate in such a manner as to at least cover a gap between the pair of the first and the second semiconductor region;
a first gate formed on the first gate insulating layer;
a second insulating layer formed to cover the first gate;
a second gate formed on the second insulating layer;
a third gate formed alongside the first gate in the silicon substrate with being insulated from the first gate and the second gate with the third insulating layer and a multilayer of at least the second insulating layer and a fourth insulating layer; and
a fifth insulating layer formed between the first gate and another first gate in a direction intersecting a direction in which the first gate and the third gate are aligned:
wherein:
one of surfaces of the first gate, which faces the second gate with the second insulating layer being formed therebetween, has a dented shape as viewed in sections which are perpendicular to the silicon substrate, one of the sections being taken in a direction extending from the first gate to the third gate and the other section being taken in a direction extending from the first gate to the fifth insulating layer.
2. The nonvolatile semiconductor memory device according to claim 1, wherein the fourth insulating layer is formed from an insulating layer material which is different from that used for forming the fifth insulating layer.
3. The nonvolatile semiconductor memory device according to claim 2, wherein the fourth insulating layer is of a silicon nitride film and the fifth insulating layer is of a silicon oxide film.
4. The nonvolatile semiconductor memory device according to claim 2, wherein the fourth insulating layer is of a silicon oxide film and the fifth insulating layer is of a silicon nitride film.
5. The nonvolatile semiconductor memory device according to claim 1, wherein a height of the first gate is below at least one of those of the fourth insulating layer and the fifth insulating layer.
6. The nonvolatile semiconductor memory device according to claim 1, wherein a height of the second gate is greater than that of the fourth insulating layer and equal to that of the fifth insulating layer.
7. The nonvolatile semiconductor memory device according to claim 1, wherein the height of the second gate is greater than that of the fifth insulating layer and equal to that of the fourth insulating layer.
8. The nonvolatile semiconductor memory device according to items claim 1, wherein one of the first gate, the second gate, and the third gate serves as an erase gate.
9. The nonvolatile semiconductor memory device according to claim 1 wherein an interpoly dielectric film formed between the first gate and the second gate is formed from a high-k material.
10. A nonvolatile semiconductor memory device comprising a memory cell, the memory cell comprising:
a first conductivity type well formed in a silicon substrate;
a second conductivity type semiconductor region which is a pair of a first semiconductor region and a second semiconductor region, the second conductivity type semiconductor region being formed in the first conductivity type well;
a first gate insulating layer formed in the silicon substrate in such a manner as to at least cover a gap between the first and the second semiconductor region of the second conductivity type semiconductor region;
a first gate formed on the first gate insulating layer;
a second insulating layer formed to cover the first gate;
a second gate formed on the second insulating layer;
a third gate adjacent to the first gate; and
a fourth insulating layer adjacent to the first gate in a direction intersecting a direction in which the first gate is adjacent to the third insulating layer;
wherein:
one of surfaces of the first gate, which faces the second gate with the second insulating layer being formed therebetween, has a dented shape as viewed in sections which are perpendicular to the silicon substrate, one of the sections being taken in a direction extending from the first gate to the third insulating layer and the other section being taken in a direction extending from the first gate to the fourth insulating layer.
11. The nonvolatile semiconductor memory device according to claim 10, wherein the third insulating layer is formed from an insulating layer material which is different from that used for forming the fourth insulating layer.
12. The nonvolatile semiconductor memory device according to claim 10, wherein the third insulating layer is of a silicon nitride film and the fourth insulating layer is of a silicon oxide film.
13. The nonvolatile semiconductor memory device according to claim 10, wherein the third insulating layer is of a silicon oxide film and the fourth insulating layer is of a silicon nitride film.
14. The nonvolatile semiconductor memory device according to claim 10, wherein a height of the first gate is below at least one of those of the third insulating layer and the fourth insulating layer.
15. The nonvolatile semiconductor memory device according to claim 10, wherein a height of the second gate is greater than that of the third insulating layer and equal to that of the fourth insulating layer.
16. The nonvolatile semiconductor memory device according to claim 10, wherein the height of the second gate is greater than that of the fourth insulating layer and equal to that of the third insulating layer.
17. The nonvolatile semiconductor memory device according to claim 10, wherein the first gate is a floating gate and the second gate serves both as a control gate and an erase gate.
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 of manufacturing an iron-based sintered alloy member having a composition consisting of 0.5 to 7% by mass of Cu, 0.1 to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen, and the balance of Fe and inevitable impurities,
the method comprising:
formulating an Fe powder, a graphite powder and a Cu alloy powder, as raw powders;
mixing the powders to form a powder mixture; and
forming the powder mixture into a green compact and sintering the green compact;
wherein the Cu alloy powder has a composition consisting of 1 to 10% by mass of Fe, 0.2 to 1% by mass of oxygen, and the balance of Cu and inevitable impurities.
2. A method of manufacturing an iron-based sintered alloy member having a composition consisting of 0.5 to 7% by mass of Cu, 0.1 to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen, 0.0025 to 1.05% by mass of Mn andor 0.001 to 0.7% by mass of Zn, and the balance of Fe and inevitable impurities,
the method comprising:
formulating an Fe powder, a graphite powder and a Cu alloy powder, as raw powders;
mixing the powders to form a powder mixture;
forming the powder mixture into a green compact and sintering the green compact,
wherein the Cu alloy powder has a composition consisting of 1 to 10% by mass of Fe, 0.2 to 1% by mass of oxygen, 0.5 to 15% mass of Mn andor 0.2 to 10% by mass of Zn, and the balance of Cu and inevitable impurities.
3. (canceled)
4. (canceled)
5. A method of manufacturing an iron-based sintered alloy member having a composition consisting of 0.5 to 7% by mass of Cu, 0.1 to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen, 0.001 to 0.14% by mass in total of at least one selected from the group consisting of Al and Si, and the balance of Fe and inevitable impurities,
the method comprising:
formulating an Fe powder, a graphite powder and a Cu alloy powder, as raw powders;
mixing the powders to form a powder mixture; and
forming the powder mixture into a green compact and sintering the green compact,
wherein the Cu alloy powder has a composition consisting of 1 to 10% by mass of Fe, 0.2 to 1% by mass of oxygen, 0.01 to 2% by mass in total of at least one selected from the group consisting of Al and Si, and the balance of Cu and inevitable impurities.
6. A method of manufacturing an iron-based sintered alloy member having a composition consisting of 0.5 to 7% by mass of Cu, 0.1to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen, 0.0025 to 1.05% by mass of Mn andor 0.001 to 0.7% bv mass of Zn, 0.001 to 0.14% by mass in total of at least one selected from the group consisting of Al and Si, and the balance of Fe and inevitable impurities,
the method comprising:
formulating an Fe powder, a graphite powder and a Cu alloy powder, as raw powders;
mixing the powders to form a powder mixture; and
forming the powder mixture into a green compact and sintering the green compact,
wherein the Cu alloy powder has a composition consisting of 1 to 10% by mass of Fe, 0.2 to 1% by mass of oxygen, and 0.5 to 15% by mass of Mn andor 0.2 to 10% by mass of Zn, 0.01 to 2% by mass in total of at least one selected from the group consisting of Al and Si, and the balance of Cu and inevitable impurities.
7. (canceled)
8. (canceled)
9. The method of manufacturing the iron-based sintered alloy member according to claim 1, wherein the Fe powder, the graphite powder and the Cu alloy powder are formulated so that the content of the graphite powder is from 0.1 to 1.2% by mass, the content of the Cu alloy powder is from 1 to 7% by mass, and the balance is composed of the Fe powder.
10. An oil pump rotor made of an iron-based sintered alloy, comprising an iron-based sintered alloy having a composition consisting of 0.5 to 7% by mass of Cu, 0.1 to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen, and the balance of Fe and inevitable impurities.
11. An oil pump rotor made of an iron-based sintered alloy, comprising an iron-based sintered alloy having a composition consisting of 0.5 to 7% by mass of Cu, 0.1 to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen, 0.0025 to 1.05% by mass of Mn andor 0.001 to 0.7% by mass of Zn, and the balance of Fe and inevitable impurities.
12. (canceled)
13. (canceled)
14. An oil pump rotor made of an iron-based sintered alloy, comprising an iron-based sintered alloy having a composition consisting of 0.5 to 7% by mass of Cu, 0.1 to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen, 0.001 to 0.14% by mass in total of at least one selected from the group consisting of Al and Si, and the balance of Fe and inevitable impurities.
15. An oil pump rotor made of an iron-based sintered alloy, comprising an iron-based sintered alloy having a composition consisting of 0.5 to 7% by mass of Cu, 0.1 to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen, 0.0025 to 1.05% by mass of Mn andor 0.001 to 0.7% by mass of Zn, 0.001 to 0.14% by mass in total of at least one selected from the group consisting of Al and Si, and the balance of Fe and inevitable impurities.
16. (canceled)
17. (canceled)
18. The oil pump rotor according to claim 10, wherein the iron-based sintered alloy has such a texture that base material cells containing Fe, as a main component, Cu and O, which are partitioned with an old Fe powder boundary formed by sintering the Fe powder, as raw powders, are aggregated to form a basis material and the base material cells partitioned with the old Fe powder boundary have such a gradient concentration that the concentration of Cu and O in the vicinity of the old Fe powder boundary is higher than the concentration of Cu and O of the center portion of the base material cell.
19. An iron-based sintered alloy which has a composition consisting of 0.5 to 10% by mass of Cu, 0.1 to 0.98% by mass of C, 0.02 to 0.3% by mass of oxygen, and the balance of Fe and inevitable impurities, and also has a texture composed of an aggregate of base material cells made of an Fe-based alloy containing C, Cu and O, which are partitioned with an old Fe powder boundary formed by sintering an Fe powder, as raw powders,
wherein the base material cells made of the Fe-based alloy containing C, Cu and O, which are partitioned with the old Fe powder boundary, have such a gradient concentration that the concentration of Cu and O in the vicinity of the old Fe powder boundary is higher than the concentration of Cu and O of the center portion of the base material cell.
20. The iron-based sintered alloy according to claim 19, wherein the base material cells made of the Fe-based alloy containing C, Cu and O, which are partitioned with the old Fe powder boundary, have such a gradient concentration that the concentration of Cu and O is maximum in the vicinity of the old Fe powder boundary, while the concentration of Cu and O decreases toward the center portion of the base material cell and reached a minimum value at the center of the base material cell.
21. A method of manufacturing the iron-based sintered alloy member of claim 19, which comprises formulating an Fe powder, a graphite powder and a Cu alloy powder having a composition consisting of 1 to 10% by mass of Fe, 0.2 to 1% by mass of oxygen, and the balance of Cu and inevitable impurities, mixing the powders to form a powder mixture, press-forming the powder mixture into a green compact and sintering the green compact in a hydrogen atmosphere containing nitrogen at a temperature of 1090 to 1300\xb0 C.
22. The method of manufacturing the iron-based sintered alloy member according to claim 2, wherein the Fe powder, the graphite powder and the Cu alloy powder are formulated so that the content of the graphite powder is from 0.1 to 1.2% by mass, the content of the Cu alloy powder is from 1 to 7% by mass, and the balance is composed of the Fe powder.
23. The method of manufacturing the iron-based sintered alloy member according to claim 5, wherein the Fe powder, the graphite powder and the Cu alloy powder are formulated so that the content of the graphite powder is from 0.1 to 1.2% by mass, the content of the Cu alloy powder is from 1 to 7% by mass, and the balance is composed of the Fe powder.
24. The method of manufacturing the iron-based sintered alloy member according to claim 6, wherein the Fe powder, the graphite powder and the Cu alloy powder are formulated so that the content of the graphite powder is from 0.1 to 1.2% by mass, the content of the Cu alloy powder is from 1 to 7% by mass, and the balance is composed of the Fe powder.
25. The oil pump rotor according to claim 11, wherein the iron-based sintered alloy has such a texture that base material cells containing Fe, as a main component, Cu and O, which are partitioned with an old Fe powder boundary formed by sintering the Fe powder, as raw powders, are aggregated to form a basis material and the base material cells partitioned with the old Fe powder boundary have such a gradient concentration that the concentration of Cu and O in the vicinity of the old Fe powder boundary is higher than the concentration of Cu and O of the center portion of the base material cell.
26. The oil pump rotor according to claim 14, wherein the iron-based sintered alloy has such a texture that base material cells containing Fe, as a main component, Cu and O, which are partitioned with an old Fe powder boundary formed by sintering the Fe powder, as raw powders, are aggregated to form a basis material and the base material cells partitioned with the old Fe powder boundary have such a gradient concentration that the concentration of Cu and O in the vicinity of the old Fe powder boundary is higher than the concentration of Cu and O of the center portion of the base material cell.
27. The oil pump rotor according to claim 15, wherein the iron-based sintered alloy has such a texture that base material cells containing Fe, as a main component, Cu and O, which are partitioned with an old Fe powder boundary formed by sintering the Fe powder, as raw powders, are aggregated to form a basis material and the base material cells partitioned with the old Fe powder boundary have such a gradient concentration that the concentration of Cu and O in the vicinity of the old Fe powder boundary is higher than the concentration of Cu and O of the center portion of the base material cell.