Patent ID: 7566934
Filing Date: 2009-07-28
Classification: H01L

Abstract:
1. A semiconductor device formed on an SOI substrate having a silicon layer formed on an insulating layer, the semiconductor device comprising: a transistor element formed in the silicon layer of the SOI substrate; an isolation film for electrically isolating the transistor element, the isolation film being formed in the silicon layer of the SOI substrate by LOCOS so that a parasitic transistor is formed; impurity diffusion regions disposed at an end of the isolation film and at a boundary of a source region of the transistor element with a channel forming region, the impurity diffusion regions having a polarity opposite to that of the source region, so that a current path due to a parasitic channel in the parasitic transistor is suppressed; and an active region containing the source region, the channel forming region and a drain region, and a gate electrode disposed over the active region; wherein a length of the active region in a gate length direction is at least 2 μm and a length of each of the impurity diffusion regions in the direction of the source region is in the range of about 0.5 to 0.7 μm.