| CPC H01L 29/7816 (2013.01) [H01L 29/045 (2013.01); H01L 29/66681 (2013.01)] | 5 Claims |
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1. A semiconductor device comprising:
a semiconductor substrate having a main surface;
a source region formed in the main surface of the semiconductor substrate;
a drain region formed in the main surface of the semiconductor substrate, the drain region being separated from the source region;
a first trench formed between the source region and the drain region and in the main surface of the semiconductor substrate;
a buried insulating film buried in the first trench;
a gate insulating film formed on a portion of the main surface of the semiconductor substrate, the portion being located between the source region and the drain region;
a gate electrode formed on the gate insulating film such that one end portion of the gate electrode is located on the buried insulating film;
a second trench formed in the main surface of the semiconductor substrate, the second trench surrounding the source region, the drain region and the gate electrode in plan view; and
an element isolation film buried in the second trench,
wherein a thickness of the element isolation film is larger than a thickness of the buried insulating film,
wherein the first trench surrounds the source region in plan view and is separated from the source region, and
wherein the second trench surrounds the first trench in plan view and is separated from the first trench in plan view.
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