1. A memory device comprising:
a dielectric layer having a top surface;
a via extending from the top surface of the dielectric layer and having a bottom portion and a top portion;
a bottom electrode within the bottom portion of the via;
a first phase change layer comprising a first phase change material within the top portion of the via and contacting the bottom electrode, the first phase change material having at least two solid phases;
a resistive heater layer comprising a heater material on the first phase change layer;
a second phase change layer comprising a second phase change material on the resistive heater layer, the second phase change material having at least two solid phases; and
a top electrode on the second phase change layer;
wherein the heater material has a resistivity greater than the most highly resistive states of the first and second phase change materials.
2. The device of claim 1, wherein the first phase change layer has a width less than a minimum feature size for a lithographic process used to form the memory device.
3. The device of claim 2, wherein the resistive heater layer, second phase change layer, and top electrode form a multi-layer stack overlying the top surface of the dielectric layer.
4. The device of claim 1, wherein the resistive heater layer has a thickness less than or equal to about 10 nm.
5. The device of claim 1, wherein the heater material has a resistivity between about 1.5 and 100 times greater than the most highly resistive states of the first and second phase change materials.
6. The device of claim 5, wherein the heater material has a resistivity between about 4 and 50 times greater than the most highly resistive states of the first and second phase change materials.
7. The device of claim 1, wherein the heater material comprises one of doped TiN, TaN, TiW, TiSiN, or TaSiN.
8. The device of claim 1, wherein the first and second phase change materials comprise the same phase change material.
9. The device of claim 1, wherein the first and second phase change materials comprise different phase change material.
10. The device of claim 1, wherein each of the first and second phase change materials comprise a combination of two or more materials from the group of Ge, Sb, Te, Se, In, Ti, Ga, Bi, Sn, Cu, Pd, Pb, Ag, S, Si, O, P, As, N and Au.
11. A method for manufacturing a memory device, the method comprising:
providing a bottom electrode extending to a top surface of a dielectric layer;
removing a portion of the bottom electrode to form a recess;
filling the recess with a first phase change material layer having at least two solid phases;
forming a layer of heater material on the first phase change layer;
forming a second phase change material layer on the layer of heater material, the second phase change material layer having at least two solid phases; and
forming a top electrode material layer on the second phase change layer;
wherein the heater material has a resistivity greater than the most highly resistive state of the first and second phase change materials.
12. The method of claim 11, wherein the filling the recess step comprises:
forming the first phase change material layer in the recess and on the top surface of the dielectric layer; and
planarizing the first phase change material layer to expose the top surface of the dielectric layer.
13. The method of claim 12, further comprising etching the layer of heater material, the second phase change material layer, and the top electrode material layer, thereby forming a multi-layer stack overlying the top surface of the dielectric layer.
14. The method of claim 11, wherein the first phase change material layer has a width less than a minimum feature size for a lithographic process used to form the memory device.
15. The method of claim 11, wherein the resistive heater layer has a thickness less than about 10 nm.
16. The method of claim 11, wherein the heater material has a resistivity between about 1.5 and 100 times greater than the most highly resistive states of the first and second phase change materials.
17. The method of claim 11, wherein the heater material comprises one of doped TiN, TaN, TiW, TiSiN, or TaSiN.
18. The method of claim 11, wherein the first and second phase change materials comprise the same phase change material.
19. The method of claim 11, wherein the first and second phase change materials comprise different phase change material.
20. The method of claim 11, wherein each of the first and second phase change materials comprise a combination of two or more materials from the group of Ge, Sb, Te, Se, In, Ti, Ga, Bi, Sn, Cu, Pd, Pb, Ag, S, Si, O, P, As, N and Au.
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 rotating electric machine, comprising:
a tubular frame;
a stator including a stator core fitted to an inner circumferential surface of the frame to be firmly fixed thereon, and a stator coil mounted on the stator core so that a load side coil end and an opposite load side coil end project from a load side end surface and an opposite load side end surface of the stator core, respectively;
a load side bracket provided on a load side of the frame, the load side bracket having a groove formed on the bracket for inserting the load side coil end therein, wherein one or more surfaces including at least an end surface among an inner circumferential surface, an outer circumferential surface, and the end surface of the load side coil end adhere closely to the inner surface of the groove through an insulating member without a gap therebetween;
an opposite load side bracket provided on an opposite load side of the frame;
a rotating shaft rotatably supported by the load side bracket and the opposite load side bracket through a load side bearing and an opposite load side bearing, respectively; and
a rotor attached to an outer circumferential surface of the rotating shaft,
wherein an outer surface of the load side coil end is pressurized and is formed so that a shape of the one or more surfaces becomes a same as a shape of the inner surface of the groove which adheres closely to the one or more surfaces.
2. The rotating electric machine according to claim 1, wherein the load side bracket is made of an aluminum alloy.
3. The rotating electric machine according to claim 1, wherein the stator core includes a plurality of teeth portions forming slots in an inner circumferential portion, and the stator coil, having an inner part formed to be longer in an axial direction thereof than that of each of the plurality of teeth portions, is mounted on each of the plurality of teeth portions.
4. The rotating electric machine according to claim 1, wherein the stator core is formed to be a cylinder, and the stator coil is put on an inner circumferential surface of the stator core with a ceramic coat formed between the stator coil and the inner circumferential surface.
5. The rotating electric machine according to claim 4, wherein the ceramic coat formed on the inner circumferential surface of the stator core is formed at a part of the inner circumferential surface of the stator core, the part touching the stator coil.
6. The rotating electric machine according to claim 1, wherein the stator coil is wound around the stator core by the distributed winding.
7. The rotating electric machine according to claim 1, wherein the stator coil comprises a wound round wire.
8. The rotating electric machine according to claim 1, wherein the insulating member comprises a ceramic coat.
9. The rotating electric machine according to claim 1, wherein the one or more surfaces includes at least the end surface among the inner circumferential surface and the end surface of the load side coil end, which adhere closely to the inner surface of the groove through the insulating member without a gap therebetween.
10. A rotating electric machine, comprising:
a tubular frame;
a stator including a stator core fitted to an inner circumferential surface of the frame to be firmly fixed thereon, and a stator coil mounted on the stator core so that a load side coil end and an opposite load side coil end project from a load side end surface and an opposite load side end surface of the stator core, respectively;
a load side bracket provided on a load side of the frame, the load side bracket having a groove formed on the bracket for inserting the load side coil end therein, wherein the load side coil end is formed using pressure to an outer surface of the load side coil end so that one or more surfaces including at least an end surface among an inner circumferential surface, an outer circumferential surface, and the end surface of the load side coil end extend along the inner surface of the groove to face the inner surface of the groove, and the one or more surfaces adhere closely to the inner surface of the groove through an insulating member without a gap between the one or more surfaces and the inner surface of the groove;
an opposite load side bracket provided on an opposite load side of the frame;
a rotating shaft rotatably supported by the load side bracket and the opposite load side bracket through a load side bearing and an opposite load side bearing, respectively; and
a rotor attached to an outer circumferential surface of the rotating shaft.
11. The rotating electric machine according to claim 10, wherein the load side bracket is made of an aluminum alloy.
12. The rotating electric machine according to claim 10, wherein the stator core includes a plurality of teeth portions forming slots in an inner circumferential portion, and the stator coil, having an inner part formed to be longer in an axial direction thereof than that of each of the plurality of teeth portions, is mounted on each of the plurality of teeth portions.
13. The rotating electric machine according to claim 10, wherein the stator core is formed to be a cylinder, and the stator coil is put on an inner circumferential surface of the stator core with a ceramic coat formed between the stator coil and the inner circumferential surface.
14. The rotating electric machine according to claim 13, wherein the ceramic coat formed on the inner circumferential surface of the stator core is formed at a part of the inner circumferential surface of the stator core, the part touching the stator coil.
15. The rotating electric machine according to claim 10, wherein the stator coil is wound around the stator core by the distributed winding.
16. The rotating electric machine according to claim 10, wherein the stator coil comprises a wound round wire.
17. The rotating electric machine according to claim 10, wherein the insulating member comprises a ceramic coat.
18. The rotating electric machine according to claim 10, wherein the one or more surfaces includes at least the end surface among the inner circumferential surface and the end surface of the load side coil end, which adhere closely to the inner surface of the groove through the insulating member without a gap therebetween.
19. A rotating electric machine, comprising:
a tubular frame;
a stator including a stator core fitted to an inner circumferential surface of the frame to be firmly fixed thereon, and a stator coil mounted on the stator core so that a load side coil end and an opposite load side coil end project from a load side end surface and an opposite load side end surface of the stator core, respectively;
a load side bracket attached to the load side end surface of the frame, the load side bracket having a groove formed on the bracket for inserting the load side coil end therein, the groove having a ceramic coating formed on an inner surface of the groove, wherein one or more surfaces including at least an end surface among an inner circumferential surface and the end surface of the load side coil end adhere closely to the inner surface of the groove through the ceramic coating without a gap therebetween;
an opposite load side bracket attached to the opposite load side end surface of the frame;
a rotating shaft rotatably supported by the load side bracket and the opposite load side bracket through a load side bearing and an opposite load side bearing, respectively; and
a rotor attached to an outer circumferential surface of the rotating shaft.