Method for fabricating semiconductor device

• US 10,236,383 B2
• Filed: 03/08/2018
• Issued: 03/19/2019
• Est. Priority Date: 04/07/2015
• Status: Active Grant

• Current Assignee: United Microelectronics Corporation
• Original Assignee: United Microelectronics Corporation
• Inventors: Feng, Li-Wei, Tsai, Shih-Hung, Lin, Chao-Hung, Hsu, Chih-Kai, Hung, Yu-Hsiang, Jenq, Jyh-Shyang
• Primary Examiner(s): Rahman, Moin M
• Application Number:
  US15/916,261
• Publication Number:
  US 20180197981A1
• Time in Patent Office: 376 Days
• Field of Search: 257 20, 257194, 257135-136, 257213-413, 257900, 257902-903, 438136, 438137, 438455-458, 438149-165, 438173, 438192, 438206, 438212, 438424, 438427, 438428, 438591
• CPC Class Codes: H01L 29/66795 with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 29/66803 with a step of doping the vertical sidewall, e.g. using tilted or multi-angled implants
• CPC Class Codes: H01L 29/785 having a channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET

Abstract

A method for fabricating semiconductor device includes the steps of: providing a substrate having a first fin-shaped structure thereon; forming a spacer adjacent to the first fin-shaped structure; using the spacer as mask to remove part of the substrate for forming a second fin-shaped structure, wherein the second fin-shaped structure comprises a top portion and a bottom portion; and forming a doped portion in the bottom portion of the second fin-shaped structure.

Claims

1. A method for fabricating semiconductor device, comprising:

providing a substrate having a first fin-shaped structure thereon;

forming a spacer adjacent to the first fin-shaped structure;

using the spacer as mask to remove part of the substrate for forming a second fin-shaped structure, wherein the second fin-shaped structure comprises a top portion and a bottom portion;

forming a doped layer on the substrate, the spacer, and the second fin-shaped structure; and

performing an anneal process to drive dopants from the doped layer into the bottom portion for forming a doped portion in the bottom portion of the second fin-shaped structure.

2. The method of claim 1, wherein the first fin-shaped structure comprises a mask layer thereon, the method comprises:

using the mask layer and the spacer as mask to remove part of the substrate for forming the second fin-shaped structure.

3. The method of claim 2, further comprising:

forming a liner on the bottom portion of the second fin-shaped structure; and

forming a hard mask on the doped layer.

4. The method of claim 3, wherein the liner comprises silicon oxide.

5. The method of claim 3, wherein the doped layer comprises borosilicate glass (BSG) or phosphosilicate glass (PSG).

6. The method of claim 3, further comprising:

performing the annealing process after forming the hard mask to form the doped region in the bottom portion of the second fin-shaped structure; and

removing the hard mask, the doped layer, and the spacer.