Semiconductor device and method for manufacturing the same

A semiconductor device, comprising:

• a semiconductor substrate of a first conductivity type;
• a first semiconductor element having a front surface structure in a main surface of the semiconductor substrate;
• a second semiconductor element having a front surface structure in the main surface of the semiconductor substrate, the front surface structure of the second semiconductor element being separated from the front surface structure of the first semiconductor element;
• a rear surface electrode for the first and second semiconductor elements;
• a first semiconductor region of a second conductivity type selectively formed in the main surface of the semiconductor substrate so as to be between the front surface structure of the first semiconductor element and the front surface structure of the second semiconductor element and so as to surround the front surface structure of the first semiconductor element and the front surface structure of the second semiconductor element;
• a second semiconductor region of the second conductivity type formed in the main surface of the semiconductor substrate outside the first semiconductor region and in contact therewith;
• a first trench filled with an insulating layer in the first semiconductor region, surrounding the front surface structure of the first semiconductor element;
• a second trench filled with an insulating layer in the first semiconductor region, surrounding the front surface structure of the second semiconductor element, the second trench being separated from the first trench;
• a third trench filled with an insulating layer in the first semiconductor region, separated from the first and second trenches and surrounding the first and second trenches so as to divide the first semiconductor region into an inner side and an outer side, thereby forming an isolation structure that includes the first and second trenches and the first semiconductor region between the first semiconductor element and the second semiconductor element, electrically isolating the front surface structure of the first semiconductor element from the front surface structure of the second semiconductor element.

A method of manufacturing a semiconductor device, comprising:

• forming a first semiconductor element and a second semiconductor element in a semiconductor substrate of a first conductivity type, the first semiconductor element having a front surface structure in a main surface of the semiconductor substrate, the second semiconductor element having a front surface structure in the main surface of the semiconductor substrate;
• forming a rear surface electrode for the first and second semiconductor elements;
• selectively forming a first semiconductor region of a second conductivity type in the main surface of the semiconductor substrate such that the first semiconductor region is located between the front surface structure of the first semiconductor element and the front surface structure of the second semiconductor element as well as surrounding the front surface structure of the first semiconductor element and the front surface structure of the second semiconductor element;
• forming a second semiconductor region of the first conductivity type in the main surface of the semiconductor substrate outside the first semiconductor region and separated therefrom;
• and
• forming at least one trench filled with an insulating layer in the first semiconductor region between the first semiconductor element and the second semiconductor element, respective ends of the at least one trench extending parallel to the main surface out of the first semiconductor region into the second semiconductor region so as to divide the first semiconductor region into a first semiconductor element side and a second semiconductor element side, thereby forming an isolation structure that includes said at least one trench filled with the insulating layer and the first semiconductor region between the first semiconductor element and the second semiconductor element, electrically isolating the front surface structure of the first semiconductor element from the front surface structure of the second semiconductor element.