Multiple dielectric FinFET structure and method

• US 7,312,502 B2
• Filed: 06/28/2006
• Issued: 12/25/2007
• Est. Priority Date: 03/18/2004
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Clark, William F. Jr., Nowak, Edward J.
• Primary Examiner(s): Andujar, Leonardo
• Assistant Examiner(s): Quinto, Kevin
• Application Number:
  US11/427,031
• Publication Number:
  US 20060231881A1
• Time in Patent Office: 545 Days
• Field of Search: None
• US Class Current: 257/347
• CPC Class Codes: H01L 21/84 the substrate being other than a semiconductor body, e.g. being an insulating body
• CPC Class Codes: H01L 21/845 including field-effect transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/1203 the substrate comprising an insulating body on a semiconductor body, e.g. SOI three-dimensional layout H01L27/0688
• CPC Class Codes: H01L 27/1211 combined with field-effect transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 29/42384 for thin film field effect transistors, e.g. characterised by the thickness or the shape of the insulator or the dimensions, the shape or the lay-out of the conductor
• 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 29/66818 the channel being thinned after patterning, e.g. sacrificial oxidation on fin
• 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

Disclosed is a method and structure for a fin-type field effect transistor (FinFET) structure that has different thickness gate dielectrics covering the fins extending from the substrate. These fins have a central channel region and source and drain regions on opposite sides of the channel region. The thicker gate dielectrics can comprise multiple layers of dielectric and the thinner gate dielectrics can comprise less layers of dielectric. A cap comprising a different material than the gate dielectrics can be positioned over the fins.

Claims

1. A semiconductor structure having at least one fin-type field effect transistor (FinFET), said semiconductor structure comprising:

a substrate;

at least one first fin extending from said substrate and having first opposing sides;

at least one second fin extending from said substrate and having second opposing sides, wherein said first fin and said second fin have different thicknesses;

a first gate dielectric covering said first opposing sides of said first fin; and

a second gate dielectric covering said second opposing sides of said second fin,

wherein said first gate dielectric has a first thickness and said second gate dielectric has a second thickness and wherein said first thickness is different from said second thickness.

2. The semiconductor structure in claim 1, all the limitations of which are incorporated herein by reference, wherein said first fin and said second fin are utilized in a multiple-fin transistor on said substrate.

3. The semiconductor structure in claim 1, all the limitations of which are incorporated herein by reference, wherein said first thickness is greater than approximately two times said second thickness.

4. The semiconductor structure in claim 1, all the limitations of which are incorporated herein by reference, wherein said first fin and said second fin are utilized in different transistors on said substrate.

5. The semiconductor structure in claim 4, all the limitations of which are incorporated herein by reference, wherein said different transistors have different voltage requirements.

6. A semiconductor structure having multiple fin-type field effect transistors (FinFETs), said semiconductor structure comprising:

a substrate; and

complementary transistors on said substrate, wherein said complementary transistors comprise;

at least one first fin for a first type transistor extending from said substrate;

at least one second fin for a second type transistor extending from said substrate,

wherein said first fin and said second fin have different thicknesses;

a first gate dielectric covering first opposing sides of said first fin; and

a second gate dielectric covering second opposing sides of said second fin,

wherein said first gate dielectric has a first thickness and said second gate dielectric has a second thickness and wherein said first thickness is different from said second thickness.

7. The semiconductor structure in claim 6, all the limitations of which are incorporated herein by reference, wherein said first type transistor and said second type transistor have different voltage requirements.

8. The semiconductor structure of claim 6, all the limitations of which are incorporated herein by reference, wherein at least one of said first type transistor and said second type transistor comprises a multiple-fin transistor.

9. The semiconductor structure in claim 6, all the limitations of which are incorporated herein by reference, wherein said first thickness is greater than approximately two times said second thickness.