Method for forming metal salicide

• US 6,703,296 B1
• Filed: 04/17/2003
• Issued: 03/09/2004
• Est. Priority Date: 04/17/2003
• Status: Active Grant

• Current Assignee: Macronix International Co., Ltd.
• Original Assignee: Macronix International Co., Ltd.
• Inventors: Lee, Chung-Yeh
• Primary Examiner(s): Goudreau, George A.
• Application Number:
  US10/249,529
• Time in Patent Office: 327 Days
• Field of Search: 438/582, 438/583, 427/509, 427/569
• US Class Current: 438/582
• CPC Class Codes: H01L 21/28061 the conductor comprising a metal or metal silicide formed by deposition, e.g. sputter deposition, i.e. without a silicidation reaction H01L21/28052 takes precedence
• CPC Class Codes: H01L 21/28518 the conductive layers comprising silicides H01L21/28537 takes precedence
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 29/456 on silicon
• CPC Class Codes: H01L 29/665 using self aligned silicidation, i.e. salicide formation of conductive layers comprising silicides H01L21/28518

Abstract

A method for forming a metal salicide layer on a shallow junction is described. A substrate having a gate structure thereon and a shallow junction therein is provided. An atomic layer deposition (ALD) process is then performed to deposit a tungsten salicide layer on the shallow junction. In the ALD process, a gaseous silicon-containing compound and a gaseous metal-containing compound that react into metal silicide are introduced alternatively onto the substrate, wherein either compound can be introduced at first. When either compound is introduced at first, the flow rate thereof is controlled so that only a single layer of molecules are adsorbed, while the flow rate of the metal-containing compound is controlled in each case so that few silicon atoms in the substrate are consumed. By repeating the two gas introduction steps, a metal salicide layer constituted of many thin layers is formed on the shallow junction.

Claims

1. A method for forming a tungsten salicide layer, comprising:

providing a substrate having a shallow junction therein; and

performing an atomic layer deposition (ALD) process to form a tungsten salicide layer on the shallow junction, the ALD process being implemented by alternatively introducing SiH₄ and WF₆ onto the substrate, wherein a flow rate of WF₆ is controlled so that few silicon atoms in the substrate are consumed.

2. The method of claim 1, wherein an inert gas is introduced after each SiH₄ or WF₆ introduction step to remove excess SiH₄ or WF₆ molecules.

3. The method of claim 2, wherein the inert gas comprises argon (Ar).

4. The method of claim 1, wherein SiH₄ is introduced at first, and a flow rate of SiH₄ is controlled so that only a single layer of SiH₄ molecules are adsorbed on the substrate.

5. The method of claim 1, wherein WF₆ is introduced at first, and the flow rate of WF₆ is controlled so that only a single layer of WF₆ molecules are adsorbed on the substrate.

6. The method of claim 1, wherein a tungsten layer is further formed on the tungsten salicide layer.

7. The method of claim 6, wherein the tungsten layer is formed with reaction of H₂ and WF₆.

8. The method of claim 1, wherein the substrate further comprises a gate structure thereon comprising a gate dielectric layer, a polysilicon gate on the gate dielectric layer and a spacer on the sidewall of the polysilicon gate, and the tungsten salicide layer is also formed on the polysilicon gate.

9. A method for forming a metal salicide layer, comprising:

providing a substrate having a shallow junction therein; and

performing an atomic layer deposition (ALD) process to form a metal salicide layer on the shallow junction, the ALD process being implemented by alternatively introducing a gaseous silicon-containing compound and a gaseous metal-containing compound that react into metal suicide onto the substrate, wherein

molecules of the silicon-containing compound or the metal-containing compound can be adsorbed on the substrate; and

a flow rate of the metal-containing compound is controlled so that few silicon atoms in the substrate are consumed.

10. The method of claim 9, wherein an inert gas is introduced after each introduction step of the silicon-containing compound or the metal-containing compound to remove excess silicon-containing compound or excess metal-containing compound.

11. The method of claim 10, wherein the inert gas comprises argon (Ar).

12. The method of claim 9, wherein a flow rate of the silicon-containing compound is the same as the flow rate of the metal-containing compound.

13. The method of claim 9, wherein the silicon-containing compound is introduced at first, and a flow rate of the silicon-containing compound is controlled so that only a single layer of molecules are adsorbed on the substrate.

14. The method of claim 9, wherein the metal-containing compound is introduced at first, and the flow rate of the metal-containing compound is controlled so that only a single layer of molecules are adsorbed on the substrate.

15. The method of claim 9, wherein the silicon-containing compound comprises SiH₄.

16. The method of claim 9, wherein the metal-containing compound comprises WF₆.

17. The method of claim 9, wherein the substrate further comprises a gate structure thereon comprising a gate dielectric layer, a polysilicon gate on the gate dielectric layer and a spacer on the sidewall of the polysilicon gate, and the metal salicide layer is also formed on the polysilicon gate.