Granted Patent B2

US 8,563,355 · App. 12/016,739 · Granted Oct 22, 2013

Abstract

Claims (27)

1. A method of making a circuit including a phase change memory cell, the method comprising:

forming a structure including silicon;

forming a transistor, the transistor including a channel region having a first portion located along a first sidewall of the structure including silicon and having a second portion located along a second sidewall of the structure including silicon, the second sidewall being an opposing sidewall to the first sidewall, wherein the forming the transistor includes:

forming a control electrode, the control electrode having a first portion adjacent to the first sidewall for controlling conductivity in the first portion of the channel region and a second portion adjacent to the second sidewall for controlling conductivity in the second portion of the channel region; and

forming a first current electrode in the structure including silicon and forming a second current electrode in the structure including silicon;

forming a separation region in the structure including silicon between the first current electrode and a contact region to form a contact sidewall on the first current electrode in the separation region;

forming a heater comprising forming a heater silicide adjacent to the contact sidewall in the separation region; and

after forming the heater, forming a phase change structure in the opening in contact with the heater silicide wherein the phase change structure exhibits a first resistive value when in a first phase state and exhibits a second resistive value when in a second phase state, wherein the phase change structure wraps around a pointed corner of the heater.

2. The method of claim 1 wherein the forming the heater silicide includes:

siliciding the contact sidewall.

3. The method of claim 1 wherein the forming the phase change structure includes forming a layer of phase change material over a wafer, the wafer including the structure, the method further comprising:

patterning the layer to leave the phase change structure in the separation region.

4. The method of claim 1 wherein the heater silicide includes cobalt.

5. The method of claim 1 wherein the forming the structure including silicon includes forming the structure including silicon having a first width, oxidizing the silicon structure to form an oxidized layer, and removing the oxidized layer, wherein first width is reduced by the oxidizing.

6. A method of forming a phase change memory cell, the method comprising:

providing a wafer having a layer including silicon located over an insulating layer;

forming a first structure including silicon and a second structure including silicon physically separated from the first structure including silicon, wherein the forming includes removing material from the layer including silicon at a location between the first structure including silicon and the second structure including silicon to form a separation region between the first structure and the second structure by which a contact sidewall is formed on a first current electrode in the separation region;

forming a transistor, the transistor including a channel region having a first portion located along a first sidewall of the first structure including silicon and having a second portion located along a second sidewall of the first structure including silicon, the second sidewall being an opposing sidewall to the first sidewall, wherein the forming the transistor includes:

forming a control electrode, the control electrode having a first portion adjacent to the first sidewall for controlling conductivity in the first portion of the channel region and a second portion adjacent to the second sidewall for controlling conductivity in the second portion of the channel region;

forming the first current electrode in the first structure including silicon and forming a second current electrode in the first structure including silicon;

forming a heater comprising forming a heater silicide adjacent to the contact sidewall in the separation region and over a portion of the first current electrode;

forming a phase change memory cell electrically coupled to the transistor by the heater along the contact sidewall, the transistor controlling current for changing a phase state of the phase change memory cell, the forming the phase change memory cell includes:

after forming the heater, forming a phase change structure in the separation and in contact with the heater along the contact sidewall and in contact with the heater over the first current electrode wherein the phase change structure exhibits a first resistive value when in a first phase state and exhibits a second resistive value when in a second phase state.

7. The method of claim 6 wherein the heater includes first and second sidewall silicide portions and the heater wraps around a corner of the silicide portions.

8. The method of claim 6 wherein the forming the heater silicide includes siliciding a second portion of the first structure to form a third silicide structure, wherein the third silicide structure physically contacts the first current electrode.

9. The method of claim 6 wherein the heater includes cobalt.

10. The method of claim 6 wherein a thickness of the phase change structure over the portion of the first current electrode is more than half and less than a full thickness of the phase change structure in the separation region.

Assignments (17)