Semiconductor device

Abstract

An active area ( 1 ) is provided with a concave part in its corner portion in a shape along a plan view. An insulating film ( 7 ) encloses this active area. A gate electrode ( 30 ) is arranged on a depressed region (DR) having an edge portion which is located on a low position due to the concave part, while a gate electrode ( 20 ) is arranged on an ordinary region (OR) having an edge portion projecting beyond the depressed region. A gate end cap (margin part) of the gate electrode ( 20 ) has a length x, while that of the gate electrode ( 30 ) has a length x+α. Thus provided is a semiconductor device causing no current defect between source/drain regions even if the active area and an insulating film defining this active area fail to satisfy the layout design following refinement of the semiconductor device.

1 . A semiconductor device comprising: 
 an active area being provided with at least one MOS transistor; and    an insulating film defining said active area, wherein    said active area is set in a shape having a concave part in a shape along a plan view,    said active area is provided with:    an ordinary region, and    a depressed region having an edge portion being depressed beyond said ordinary region due to presence of said concave part,    said at least one MOS transistor includes:    a first MOS transistor being formed on said depressed region, and    a second MOS transistor being formed on said ordinary region, and    a length of a margin part of a first gate electrode constructing said first MOS transistor in said depressed region is set to be larger than that of a margin part of a second gate electrode constructing said second MOS transistor in said ordinary region, wherein a length of the margin part of the second gate electrode is X, the length of the margin part of the first gate electrode is X+α where 0<α≦X, wherein    said concave part is formed on a corner portion of said active area, and the length of said margin part of said first gate electrode is set at the total of the length of said margin part of said second gate electrode and a length being equal to a depression length in said concave part.    
   
   
       2 . A semiconductor device comprising: 
 an active area being provided with at least one MOS transistor; and    an insulating film defining said active area, wherein    said active area is set in a shape having a concave part in a shape along a plan view,    said active area is provided with:    an ordinary region, and    a depressed region having an edge portion being depressed beyond said ordinary region due to presence of said concave part,    said at least one MOS transistor includes:    a first MOS transistor being formed on said depressed region, and    a second MOS transistor being formed on said ordinary region, and    a length of a margin part of a first gate electrode constructing said first MOS transistor in said depressed region is set to be larger than that of a margin part of a second gate electrode constructing said second MOS transistor in said ordinary region, wherein a length of the margin part of the second gate electrode is X, the length of the margin part of the first gate electrode is X+α where 0<α≦X, wherein    said concave part is formed on a corner portion of said active area, and    the length of said margin part of said first gate electrode is set at the total of:    the length of said margin part of said second gate electrode, and    the length of a portion between said edge portion of said depressed region and an intersection between a virtual line being set to connect first and second convex corner portions of said active area in said concave part and said first gate electrode.    
   
   
       3 . A semiconductor device comprising: 
 an active area being provided with at least one MOS transistor; and    an insulating film defining said active area, wherein    said active area is set in a shape having a concave part in a shape along a plan view,    said active area is provided with:    an ordinary region, and    a depressed region having an edge portion being depressed beyond said ordinary region due to presence of said concave part,    said at least one MOS transistor includes:    a first MOS transistor being formed on said depressed region, and    a second MOS transistor being formed on said ordinary region, and    a margin part of a first gate electrode constructing said first MOS transistor is set in a shape having a bent portion being bent at a prescribed angle to extend in a direction separating from said ordinary region.    
   
   
       4 . The semiconductor device in accordance with  claim 3 , wherein 
 said concave part is formed on a corner portion of said active area,    said prescribed angle is 90°,    said depressed region includes a first edge portion being perpendicular to said first gate electrode and a second edge portion being parallel to said first gate electrode,    said bent portion extends to be substantially in contact with or not in contact with said first edge portion of said depressed region, and    the length of said bent portion is so set that its forward end portion projects beyond said second edge portion of said depressed region by a distance being equal to the length of a margin part of a second gate electrode constructing said second MOS transistor.    
   
   
       5 . The semiconductor device in accordance with  claim 3 , wherein 
 said concave part is formed on a corner portion of said active area,    said prescribed angle is 90°,    said depressed region includes a first edge portion being perpendicular to said first gate electrode and a second edge portion being parallel to said first gate electrode,    said bent portion extends to be not in contact with said first edge portion of said depressed region, and    the length of said bent portion is so set that its forward end portion projects beyond an intersect position between a virtual line being set to connect first and second convex corner portions of said active area in said concave part and said first gate electrode by a distance being equal to the length of a margin part of a second gate electrode constructing said second MOS transistor.    
   
   
       6 . The semiconductor device in accordance with  claim 3 , wherein 
 said concave part is formed on a corner portion of said active area,    said bent portion is bent about an intersect position between a virtual line being set to connect first and second convex corner portions of said active area in said concave part and said first gate electrode,    said prescribed angle is smaller than 90°, and    the length of said bent portion is so set that its forward end portion projects beyond said intersect position by a distance being equal to the length of a margin part of a second gate electrode constructing said second MOS transistor.