Sense line and cell contact

Patent metadata

Field	Value
Publication number	US-2023345708-A1
Application number	US-202217729450-A
Country	US
Kind code	A1
Filing date	Apr 26, 2022
Priority date	Apr 26, 2022
Publication date	Oct 26, 2023
Grant date	—

Abstract

Methods, apparatuses, and systems related to a sense line and cell contact for a semiconductor structure are described. An example apparatus includes a first source/drain region and a second source/drain region, where the first source/drain region and the second source/drain region are separated by a channel, a gate opposing the channel, a sense line material coupled to the first source/drain region by a cell contact, where the cell contact is made from a combination of a first polysilicon material and a second polysilicon material, and a storage node coupled to the second source/drain region.

First claim

What is claimed is:

1 . An apparatus, comprising:
a first source/drain region and a second source/drain region, wherein the first source/drain region and the second source/drain region are separated by a channel; a gate opposing the channel; a sense line coupled to the first source/drain region by a cell contact, wherein the cell contact is made from a combination of a first polysilicon material and a second polysilicon material; and a storage node coupled to the second source/drain region.

2 . The apparatus of claim 1 , wherein the second polysilicon material that is deposited to make the cell contact has a greater dopant concentration than the first polysilicon material.

3 . The apparatus of claim 2 , wherein a portion of the second polysilicon material that is deposited to make the cell contact is selectively removed prior to depositing a sense line material.

4 . The apparatus of claim 1 , wherein the apparatus is a buried recessed access device (BRAD).

5 . The apparatus of claim 3 , wherein the sense line material has a width from 60 to 80 angstroms.

6 . The apparatus of claim 5 , wherein the sense line material has a height from 250 to 300 angstroms.

7 . The apparatus of claim 3 , wherein the sense line material comprises ruthenium.

8 . The apparatus of claim 1 , wherein at least a portion of dopant of the second polysilicon material is diffused into the first polysilicon material to make a uniformly doped material.

9 . A method, comprising:
forming an opening in a semiconductor structure; depositing a first polysilicon material in the opening; depositing a second polysilicon material in the opening on the first polysilicon material, wherein the second polysilicon material has a greater dopant concentration than the first polysilicon material; depositing a mask material on the second polysilicon material; forming a trench in the mask material, the second polysilicon material, and the first polysilicon material; depositing a dielectric material in the trench; removing a portion of the second polysilicon material to make a sense line material deposition space; and depositing a sense line material in the sense line material deposition space.

10 . The method of claim 9 , further comprising conformally depositing a spacer material in the trench prior to depositing the dielectric material in the trench.

11 . The method of claim 10 , further comprising planarizing the spacer material, the mask material, and the dielectric material prior to removing a portion of the second polysilicon material.

12 . The method of claim 9 , further comprising planarizing the sense line material.

13 . The method of claim 12 , further comprising forming a cap material on the planarized sense line material.

14 . The method of claim 13 , wherein the cap material is a nitride material.

15 . The method of claim 9 , wherein the sense line material deposition space has an aspect ratio of about 4.

16 . The method of claim 9 , wherein the first polysilicon material is deposited to a thickness 200 to 450 angstroms.

17 . The method of claim 9 , wherein the second polysilicon material is deposited to a thickness 200 to 450 angstroms.

18 . An apparatus, comprising:
a cell contact made from a first polysilicon material and a second first polysilicon material that is formed on the first polysilicon material, wherein the second polysilicon material has a greater dopant concentration than the first polysilicon material; a source/drain region, wherein the cell contact is formed on the source/drain region; and a sense line material, wherein the sense line material is formed on the cell contact.

19 . The apparatus of claim 18 , further comprising a capacitor coupled to the sense line.

20 . The apparatus of claim 18 , wherein the apparatus is s a buried recessed access device (BRAD) that is part of a dynamic random access memory (DRAM) array.

Assignees

• Micron Technology Inc

Inventors

• Wang Kuo-Chen
• Mcdaniel Terrence B
• Benson Russell A
• Nair Vinay

Classifications

• H01L27/10885 Primary

  Electricity · mapped topic

• H01L27/10888

  Electricity · mapped topic

• H01L27/10897

  Electricity · mapped topic

• H10B12/482 Primary

  Bit lines · CPC title

• H10B12/485

  Bit line contacts · CPC title