Semiconductor device

A semiconductor device, comprising:

• a semiconductor layer above a main face of a semiconductor substrate, with a buried insulating layer disposed between the semiconductor substrate and the semiconductor layer;
• a body region of a first conductivity type in an upper portion of the semiconductor layer;
• a drain region of a second conductivity type in the upper portion of the semiconductor layer and spaced apart from the body region;
• a source region of the second conductivity type in a surface of the body region;
• a drift region of the second conductivity type between the drain region and the body region in the semiconductor layer;
• an insulating region between the body region and the drain region in a surface of the semiconductor layer;
• a gate insulating film extending over a portion of the body region up to an edge of the insulating region in a surface of the semiconductor layer;
• a gate electrode extending over a portion of the gate insulating film and a portion of the insulating region;
• and
• an electrode on the source region and an electrode on the drain region, wherein
• in a plan view:
• the source region and the drain region extend along a longitudinal direction and are disposed side-by-side in a lateral direction, the longitudinal direction being a direction along a longer side of sides facing each other, the lateral direction being a direction perpendicular to the longitudinal direction;
• and
• the body region and the insulating region extend along the longitudinal direction and are disposed such that one of the body region and the insulating region surrounds the other of the body region and the insulating region in a layout, the layout including a first edge line which indicates an edge of the insulating region and a second edge line which indicates an edge of the body region, the first edge line and the second edge line passing beneath the gate electrode,
• the second edge line forms a boundary between the body region and the semiconductor layer which have impurity concentrations or conductivity types different from each other, and
• in the plan view:
• the first edge line and the second edge line each have:
• straight portions that face each other and extend along the longitudinal direction;
• and curved portions each connecting ends of the straight portions either by a polygonal line forming an obtuse vertex angle or a curved line including an arc;
• in the straight portions, the second edge line indicating the body region includes a portion located nearer, in the lateral direction, to the source region than the first edge line indicating the insulating region;
• in the curved portions, the first edge line indicating the insulating region includes a portion located nearer, in the longitudinal direction, to the source region than the second edge line indicating the body region;
• the first edge line intersects with the second edge line at an intersection;
• and
• at the intersection, an angle made by the first edge line and the second edge line is acute, the first edge line and the second edge line forming a space that becomes narrower in the longitudinal direction.

A semiconductor device, comprising:

• a semiconductor layer of a first conductivity type above a main face of a semiconductor substrate, with a buried insulating layer disposed between the semiconductor substrate and the semiconductor layer;
• a body region of the first conductivity type in an upper portion of the semiconductor layer;
• a drain region of a second conductivity type in the upper portion of the semiconductor layer and spaced apart from the body region;
• a source region of the second conductivity type in a surface of the body region;
• a drift region of the second conductivity type between the drain region and the body region in the semiconductor layer;
• an insulating region between the body region and the drain region in a surface of the semiconductor layer;
• a gate insulating film extending over a portion of the body region up to an edge of the insulating region in a surface of the semiconductor layer;
• a gate electrode extending over a portion of the gate insulating film and a portion of the insulating region;
• and
• an electrode on the source region and an electrode on the drain region, wherein
• in a plan view:
• the source region and the drain region extend along a longitudinal direction and are disposed side-by-side in a lateral direction, the longitudinal direction being a direction along a longer side of sides facing each other, the lateral direction being a direction perpendicular to the longitudinal direction;
• and
• the drift region and the insulating region extend along the longitudinal direction and are disposed such that one of the drift region and the insulating region surrounds the other of the drift region and the insulating region in a layout, the layout including a first edge line indicating an edge of the insulating region and a third edge line indicating an edge of the drift region, the first edge line and the third edge line passing beneath the gate electrode,
• the third edge line forms a boundary between the drift region and the semiconductor layer which have conductivity types different from each other, and
• in the plan view:
• the first edge line and the third edge line each have:
• straight portions that face each other and extend along the longitudinal direction;
• and curved portions each connecting ends of the straight portions either by a polygonal line forming an obtuse vertex angle or a curved line including an arc;
• in the straight portions, the third edge line indicating the drift region includes a portion located nearer, in the lateral direction, to the source region than the first edge line indicating the insulating region;
• in the curved portions, the first edge line indicating the insulating region includes a portion located nearer, in the longitudinal direction, to the source region than the third edge line indicating the drift region;
• the first edge line intersects with the third edge line at an intersection;
• and
• at the intersection, an angle made by the first edge line and the third edge line is acute, the first edge line and the third edge line forming a space that becomes narrower in the longitudinal direction.