Semiconductor apparatus having high withstand voltage

A semiconductor apparatus comprising:

• a semiconductor substrate including a first element formation region and a second element formation region as an island region that is surrounded by a trench region, the trench region electrically isolating the island region from the first element formation region;
• a buffer region surrounding the trench region for preventing an electrical interference between the island region and the first element formation region;
• a source region and a drain region provided in the island region, a first one of the source region and the drain region being looped to be concentrically provided around a second one of the source region and the drain region;
• a source electrode and a drain electrode respectively provided on the source region and the drain region, a first one of the source electrode and the drain electrode connected to the first one of the source region and the drain region, and extending adjacently to the trench region more than a second one of the source electrode and the drain electrode;
• a gate electrode provided over a portion of the island region between the source region and the drain region;
• and
• an auxiliary electrode provided between the trench region and the first one of the source electrode and the drain electrode,
• wherein when a first voltage having a specific polarity is applied to the first one of the source electrode and the drain electrode, a second voltage having the specific polarity is applied to the auxiliary electrode.

A semiconductor apparatus comprising:

• a support substrate;
• an insulation layer provided on the support substrate;
• a semiconductor layer provided on the insulation layer and including a first island region and a second island region respectively surrounded by a first trench region and a second trench region to be electrically isolated from one another;
• a first semiconductor element provided in the first island region and including:
• a first source region and a first drain region provided in the first island region, a first one of the first source region and the first drain region being looped around a second one of the first source region and the first drain region;
• a first source electrode and a first drain electrode respectively provided on the first source region and the first drain region;
• and
• a first gate electrode provided over a portion of the first island region between the first source region and the first drain region;
• and
• support substrate connection means electrically connected to the support substrate for applying a voltage to the support substrate so that a potential difference between the support substrate and the first one of the first source region and the first drain region becomes small.