Patent ID: 6953975
Filing Date: 2005-10-11
Classification: G11C,H01L,Y10S

Abstract:
1. A semiconductor device formed on a single substrate comprising: an input and output circuit; a memory circuit having a plurality of SRAM memory cells; and a logic circuit; wherein each of said plurality of SRAM memory cells has a first and second driver MISFET, a first and second transfer MISFET, and a first and second load MISFET, wherein said input and output circuit has a plurality of first MISFETs and second MISFETs, wherein said logic circuit has a plurality of third, fourth, fifth, and sixth MISFETs, wherein said plurality of first MISFETs, which are n channel type, have a first threshold voltage and have gate insulating films of first thickness, wherein said plurality of second MISFETs, which are p channel type, have a second threshold voltage and have gate insulating films of said first thickness, wherein said plurality of third MISFETs, which are n channel type, have a third threshold voltage and have gate insulating films of second thickness, which is thinner than said first thickness, wherein said plurality of fourth MISFETs, which are p channel type, have a fourth threshold voltage and have gate insulating films of said second thickness, wherein said plurality of fifth MISFETs, which are n channel type, have a fifth threshold voltage and have gate insulating films of said second thickness, wherein said plurality of sixth MISFETs, which are p channel type, have a sixth threshold voltage and have gate insulating films of said second thickness, wherein said first threshold voltage is larger than said third threshold voltage, wherein the absolute value of said second threshold voltage is larger than the absolute value of said fourth threshold voltage, wherein said third threshold voltage is larger than said fifth threshold voltage, wherein the absolute value of said fourth threshold voltage is larger than the absolute value of said sixth threshold voltage, wherein said first and second transfer MISFETs, which are n channel type, have said fifth threshold voltage and have gate insulating films of said second thickness, wherein said first and second load MISFETs, which are p channel type, have said fourth threshold voltage and have gate insulating films of said second thickness.