Granted Patent B2

US 7,955,958 · App. 12/027,675 · Granted Jun 7, 2011

Abstract

Claims (34)

1. A method of producing a PN junction comprising:

providing a substrate comprising at least one conductive portion;

forming an insulating layer on the substrate;

forming a via through the insulating layer to provide an exposed surface of the at least one conductive portion;

forming a seed material on the exposed portion of the at least one conductive portion of the substrate;

forming amorphous Si on at least the seed material;

converting at least a portion of the amorphous Si to provide crystalline Si; and

forming a first dopant region abutting a second dopant region in the crystalline Si, wherein the forming of the first dopant region in the crystalline Si comprises implanting a P-type dopant and the forming the second dopant region comprises implanting an N-type dopant.

2. The method of claim 1 , wherein the crystalline Si comprises polycrystalline Si or a single crystal of Si.

3. The method of claim 1 , wherein the seed material comprises Ni, W, Al, Pt, Pd, Ge, Co, NiSi, CoSi, TiSi, WSi or alloys thereof.

4. The method of claim 1 , wherein the seed material has a thickness ranging from about 2 nm to about 100 nm.

5. The method of claim 1 , wherein the converting of the at least the portion of the amorphous Si into the crystalline Si comprises increasing a temperature of the amorphous Si to greater than about 400° C. and less than about 700° C. for a time period ranging from about 1 hour to about 24 hours.

6. The method of claim 1 , wherein the converting of the at least the portion of the amorphous Si into the crystalline Si comprises an annealing process comprising furnace anneal, laser anneal, rapid thermal anneal or combinations thereof.

7. A method of forming a memory device comprising:

providing a substrate comprising at least one conductive portion;

forming a seed material on the at least one conductive portion of the substrate;

forming amorphous Si on at least the seed material;

converting at least a portion of the amorphous Si to crystalline Si;

forming a PN junction in the crystalline Si, wherein the forming of the PN junction comprises implanting the crystalline Si to provide a first dopant region of P-type dopants, and a second dopant region of N-type dopants; and

forming a memory cell in contact with the PN junction.

8. The method of claim 7 , wherein the forming of the memory cell comprises:

forming a silicide contact on a dopant region of the PN junction;

forming an electrode atop the silicide contact; and

forming a phase change memory material atop the electrode.

9. The method of claim 8 further comprising forming an insulating layer on the substrate and forming a via through the insulating layer to an exposed surface of the at least one conductive portion, wherein the step of the forming of the amorphous Si on the seed material substantially fills the via with the amorphous Si.

10. The method of claim 9 further comprising:

forming a barrier metal atop the phase change memory material; and

etching the barrier metal and phase change memory material to provide a barrier metal/phase change memory material stack.

11. The method of claim 10 , wherein the width of the barrier metal/phase change memory material stack is greater than the width of the electrode.

12. The method of claim 11 , wherein the forming of the electrode comprises:

recessing the crystalline Si below an upper surface of the insulating layer to expose sidewalls of the via;

forming spacers on sidewalls of the via; and

depositing a barrier metal in the via atop the silicide contact.

13. The method of claim 8 , wherein the seed material comprises Ni, Al, Pt, Pd, Ge, Co, W, NiSi, CoSi, TiSi, WSi or alloys thereof.

Assignments (11)