Semiconductor device and method for fabricating the same

• US 6,445,047 B1
• Filed: 10/25/2000
• Issued: 09/03/2002
• Est. Priority Date: 10/26/1999
• Status: Expired due to Term

• Current Assignee: Godo Kaisha IP Bridge 1 (IP Bridge, Inc.)
• Original Assignee: Matsushita Electric Corporation (Panasonic Holdings Corporation)
• Inventors: Yamada, Takayuki, Moriwaki, Masaru
• Primary Examiner(s): Elms, Richard
• Assistant Examiner(s): MENZ, DOUGLAS M
• Application Number:
  US09/695,381
• Time in Patent Office: 678 Days
• Field of Search: 257/368, 257/315, 257/382, 257/390, 257/391, 257/383, 438/199
• US Class Current: 257/391
• CPC Class Codes: H01L 21/82345 gate conductors with different gate conductor materials or different gate conductor implants, e.g. dual gate structures
• CPC Class Codes: H01L 29/495 the conductor material next to the insulator being a simple metal, e.g. W, Mo H01L29/4908, H01L29/4983 take precedence
• CPC Class Codes: H01L 29/4966 the conductor material next to the insulator being a composite material, e.g. organic material, TiN, MoSi2 H01L29/4908, H01L29/4983 take precedence

Abstract

A semiconductor device includes: a first-surface-channel-type MOSFET having a first threshold voltage; and a second-surface-channel-type MOSFET with a second threshold voltage having an absolute value greater than an absolute value of said first threshold voltage. The first-surface-channel-type MOSFET includes: a first gate insulating film formed on a semiconductor substrate; and a first gate electrode, which has been formed out of a poly-silicon film over the first gate insulating film. The second-surface-channel-type MOSFET includes: a second gate insulating film formed on the semiconductor substrate; and a second gate electrode, which has been formed out of a refractory metal film over the second gate insulating film. The refractory metal film is made of a refractory metal or a compound thereof.

Claims

1. A semiconductor device comprising:

a first-surface-channel-type MOSFET with a first threshold voltage; and

a second-surface-channel-type MOSFET with a second threshold voltage having an absolute value greater than an absolute value of said first threshold voltage,

wherein the first-surface-channel-type MOSFET includes;

a first gate insulating film formed on a semiconductor substrate; and

a first gate electrode, which has been formed out of a poly-silicon film formed directly on the first gate insulating film, and

wherein the second-surface-channel-type MOSFET includes;

a second gate insulating film formed on the semiconductor substrate; and

a second gate electrode, which has been formed out of a refractory metal film formed directly on the second gate insulating film, the refractory metal film being made of a refractory metal or a compound thereof.

2. The device of claim 1, wherein a dopant concentration in the channel region of the second-surface-channel-type MOSFET is lower than a dopant concentration in the channel region of the first-surface-channel-type MOSFET.

3. The device of claim 1, wherein the first-surface-channel-type MOSFET is formed in a logic circuit block of the semiconductor substrate, and

wherein the second-surface-channel-type MOSFET controls power to be supplied to the logic circuit block.

4. The device of claim 1, wherein the first-surface-channel-type MOSFET is formed in a logic circuit block of the semiconductor substrate, and

wherein the second-surface-channel-type MOSFET is formed in a memory cell block of the semiconductor substrate, and

wherein the second gate insulating film is thicker than the first gate insulating film.