Optimized buried strap formation utilizing polycrystalline SixC1-x
OwnerPaul Wensley, Kevin McStayinventors
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Abstract
A method of forming a buried strap for a memory device includes in-situ doping a semiconductor material during deposition with propane and a dopant to form a polycrystalline buried strap comprising carbon. A barrier layer comprising carbon, such as SiC or SixC1-x, or both, is formed within the buried strap that controls or slows down dopants from migrating to an adjacent outdiffusion region within the substrate. A heavily doped polysilicon region may be formed beneath the carbon-containing buried strap, which reduces the trench semiconductor material resistance.
Claims24
A method for forming a buried strap of a memory device, comprising:
- providing a memory device, the memory device having a substrate with at least one trench capacitor formed therein, the trench capacitor including a fill material comprising a first semiconductor material;
- recessing the first semiconductor material of the at least one trench capacitor below a top surface of the substrate;
- and
- depositing a second semiconductor material over the recessed first semiconductor fill material in the presence of a carbon-containing gas, wherein the second semiconductor material forms a buried strap.
The method according to claim 8, wherein the carbon content comprises 2 to 49% of the buried strap material.
A method of manufacturing a memory device, comprising:
- providing a workpiece, the workpiece comprising a semiconductor material substrate;
- forming at least one memory cell within the workpiece, the at least one memory cell comprising a trench capacitor, the trench capacitor including a fill material comprising a first semiconductor material;
- recessing the first semiconductor material of the at least one trench capacitor below a top surface of the substrate;
- and
- depositing a second semiconductor material over the recessed first semiconductor fill material in the presence of a carbon-containing gas and a dopant, wherein the second semiconductor material forms a buried strap.
A memory device, comprising:
- a workpiece, the workpiece comprising a semiconductor material substrate;
- at least one memory cell within the workpiece, the at least one memory cell comprising a trench capacitor, the trench capacitor including a fill material comprising a first semiconductor material, the fill material being recessed below a top surface of the substrate;
- and
- a second semiconductor material disposed over and abutting the recessed first semiconductor fill material, wherein the second semiconductor material forms a buried strap, wherein the second semiconductor material comprises a dopant and carbon.
Dependencies are inferred from the claim text.