Method of forming carbon-containing silicon nitride layer

• US 7,371,649 B2
• Filed: 09/13/2006
• Issued: 05/13/2008
• Est. Priority Date: 09/13/2005
• Status: Active Grant

• Current Assignee: United Microelectronics Corporation
• Original Assignee: United Microelectronics Corporation
• Inventors: Cheng, Po-Lun
• Primary Examiner(s): DANG, TRUNG Q
• Application Number:
  US11/531,283
• Publication Number:
  US 20070059870A1
• Time in Patent Office: 608 Days
• Field of Search: 438/784, 438/791, 438/303, 257/E21.435
• US Class Current: 438/303
• CPC Class Codes: C23C 16/36 Carbonitrides
• CPC Class Codes: H01L 21/02167 the material being a silicon carbide not containing oxygen, e.g. SiC, SiC:H or silicon carbonitrides H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 29/6656 using multiple spacer layers, e.g. multiple sidewall spacers
• CPC Class Codes: H01L 29/6659 with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET
• CPC Class Codes: H01L 29/7833 with lightly doped drain or source extension, e.g. LDD MOSFET's; DDD MOSFET's for thin film transistors H01L29/78618

Abstract

A method for forming a carbon-containing silicon nitride layer with superior uniformity by low pressure chemical vapor deposition (LPCVD) using disilane, ammonia and at least one carbon-source precursor as reactant gases is provided.

Claims

1. A method for forming a gate, comprising:

providing a substrate having a gate dielectric layer thereon;

forming a conductive layer on the gate dielectric layer;

patterning the conductive layer and the gate dielectric layer to form a gate electrode;

forming offset spacers on the sidewalls of the gate electrode, the material of the offset spacers is carbon-containing silicon nitride;

forming a material layer over the substrate and covering the gate electrode, wherein the material layer comprises a carbon-containing silicon nitride layer formed by low pressure chemical vapor deposition (LPCVD) using disilane, ammonia and at least a carbon-source precursor as reactant gases;

etching back the material layer to form spacers over sidewalls of the gate electrode; and

forming a source/drain region in the substrate.

2. The method according to claim 1, wherein the carbon-containing silicon nitride layer has a carbon content higher than 9%.

3. The method according to claim 2, wherein the carbon-containing silicon nitride layer is formed by a single wafer tool.

4. The method according to claim 1, the step of forming the offset spacers comprises:

forming a carbon-containing silicon nitride offset material layer over the substrate; and

etching back the carbon-containing silicon nitride offset material layer to form the offset spacers on the sidewalls of the gate electrode.

5. The method according to claim 4, wherein the carbon-containing silicon nitride offset material layer is formed by low pressure chemical vapor deposition (LPCVD) using disilane, ammonia and at least a carbon-source precursor as reactant gases.

6. The method according to claim 5, wherein the carbon-containing silicon nitride offset material layer has a carbon content higher than 9%.

7. The method according to claim 5, wherein the carbon-containing silicon nitride offset material layer is formed by a single wafer tool.

8. The method according to claim 1, wherein the carbon-source precursor is selected from the group consisting of TEASAT (triethylarsenate, C₆H₁₅AsO₄), Trans-LC (C₂H₂Cl₂), TCS SiHCl₃),TMAl (trimethyl aluminum Al(CH₃)₃), C₂H₄, C₃H₆, TEB (triethylborate, B(OC₂H₅)₃), TEPO (triethylphosphate, PO(C₂H₅O)₃), TDMAT (tetrakis-dimethylamino titanium, Ti[N(CH₃)₂]₄) and combinations thereof.

9. The method according to claim 5, wherein the carbon-source precursor is selected from the group consisting of TEASAT (triethylarsenate, C₆H₁₅AsO₄), Trans-LC (C₂H₂Cl₂), TCS trichlorosilane, SiHCl₃), TMAl (trimethyl aluminum, Al(CH₃)₃), C₂H₄, C₃H₆, TEB (triethylborate, B(OC₂H₅)₃), TEPO (triethylphosphate, PO(C₂H₅O)₃), TDMAT (tetrakis-dimethylamino titanium, Ti[N(CH₃)₂]₄) and combinations thereof.

10. The method according to claim 1, wherein the carbon-containing silicon nitride layer has a carbon content ranging from about 9% to about 30%.

11. The method according to claim 1, wherein a gas flow rate of disilane (Si₂H₆) is less than 50 sccm (standard cubic centimeter per minute).

12. The method according to claim 1, wherein a gas flow rate of the carbon-source precursor is less than 2 slm (standard liter per minute).

13. The method according to claim 1, wherein a reaction pressure is below 250 Torr.

14. The method according to claim 1, wherein a reaction temperature is below 800°

C.