Semiconductor integrated circuit

Abstract

The semiconductor integrated circuit has so-called SOI type first MOS transistors (MNtk, MPtk) and second MOS transistors (MNtn, MPtn). The first MOS transistors have a gate isolation film thicker than that the second MOS transistors have. The first and second MOS transistors constitute a power-supply-interruptible circuit ( 6 ) and a power-supply-uninterrupted circuit ( 7 ). The power-supply-interruptible circuit has the first MOS transistors each constituting a power switch ( 10 ) between a source line (VDD) and a ground line (VSS), and the second MOS transistors connected in series with the power switch. A gate control signal for the first MOS transistors each constituting a power switch is made larger in amplitude than that for the second MOS transistors. This enables power-source cutoff control with a high degree of flexibility commensurate with the device isolation structure, which an SOI type semiconductor integrated circuit has originally.

1 - 20 . (canceled) 
     
     
         21 . A semiconductor integrated circuit, comprising:
 a silicon-on-insulator (SOI) substrate including a silicon substrate, an insulating layer over the silicon substrate and a silicon layer over the insulating layer;   a first circuit block and a second circuit block in the SOI substrate,
 the first and second circuit blocks including a plurality of first MOSFETs each having a gate electrode, a gate insulating film, a source region, a drain region and a body region in which a channel is formed, 
 the source region, the drain region and the body region being formed in the silicon layer of the SOI substrate; 
   a low voltage power line electrically coupled to the first and second circuit blocks;   a high voltage power line supplying a higher voltage than the low voltage power line, electrically coupled to the first and second circuit blocks; and   a power switch which can shut down power supply from the low voltage power line to the first circuit block.   
     
     
         22 . A semiconductor integrated circuit according to  claim 21 ,
 wherein the power switch is comprised of a second MOSFET having a gate electrode, a gate insulating film, a source region, a drain region and a body region in which a channel is formed, and   wherein a thickness of the gate insulating film of the second MOSFET is greater than that of the first MOSFET.   
     
     
         23 . A semiconductor integrated circuit according to  claim 21 ,
 wherein the first circuit block and the second circuit block are separated by shallow trench isolation.   
     
     
         24 . A semiconductor integrated circuit according to  claim 21 ,
 wherein power consumption of the semiconductor integrated circuit when the power switch shuts down the power supply is lower than that when the power switch electrically couples the low voltage power line to the first circuit block.   
     
     
         25 . A semiconductor integrated circuit, comprising:
 a silicon-on-insulator (SOI) substrate including a silicon substrate, an insulating layer over the silicon substrate and a silicon layer over the insulating layer;   a first circuit block and a second circuit block in the SOI substrate,
 the first and second circuit blocks including a plurality of first MOSFETs each having a gate electrode, a gate insulating film, a source region, a drain region and a body region in which a channel is formed, 
 the source region, the drain region and the body region being formed in the silicon layer of the SOI substrate; 
   a low voltage power line electrically coupled to the first and second circuit blocks;   a high voltage power line supplying a higher voltage than the low voltage power line, electrically coupled to the first and second circuit blocks; and   a power switch which can shut down power supply from the high voltage power line to the first circuit block.   
     
     
         26 . A semiconductor integrated circuit according to  claim 25 ,
 wherein the power switch is comprised of a second MOSFET having a gate electrode, a gate insulating film, a source region, a drain region and a body region in which a channel is formed, and   wherein a thickness of the gate insulating film of the second MOSFET is greater than that of the first MOSFET.   
     
     
         27 . A semiconductor integrated circuit according to  claim 25 ,
 wherein the first circuit block and the second circuit block are separated by shallow trench isolation.   
     
     
         28 . A semiconductor integrated circuit according to  claim 25 ,
 wherein power consumption of the semiconductor integrated circuit when the power switch shuts down the power supply is lower than that when the power switch electrically couples the high voltage power line to the first circuit block.