Insulating-gate bipolar transistors including a reverse conducting diode

A structure for an insulating gate bipolar transistor, the structure comprising:

• a semiconductor substrate comprising silicon carbide, the semiconductor substrate having a front surface, a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, and a back surface opposite from the front surface, the first semiconductor layer including a first section, a second section, and a first trench laterally between the first section and the second section, the first semiconductor layer having a first conductivity type, and the second semiconductor layer and the third semiconductor layer having a second conductivity type opposite from the first conductivity type;
• and
• a gate electrode at the front surface of the semiconductor substrate,
• wherein the first section of the first semiconductor layer adjoins a first portion of the second semiconductor layer, the second section of the first semiconductor layer adjoins a second portion of the second semiconductor layer, the first trench has a trench bottom that is coextensive with a third portion of the second semiconductor layer, the first section of the first semiconductor layer is arranged between the first portion of the second semiconductor layer and the back surface, the second section of the first semiconductor layer is arranged between the second portion of the second semiconductor layer and the back surface, the semiconductor substrate comprises a bulk substrate including a first section and a second section, the first section of the first semiconductor layer is arranged between the first section of the bulk substrate and the first portion of the second semiconductor layer, the second section of the first semiconductor layer is arranged between the second section of the bulk substrate and the second portion of the second semiconductor layer, the bulk substrate has the second conductivity type, and the bulk substrate is heavily doped.

A method of forming a structure for an insulating gate bipolar transistor, the method comprising:

• forming a gate electrode at a front surface of a semiconductor substrate, wherein the semiconductor substrate comprises silicon carbide, the semiconductor substrate includes a bulk substrate, a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, and a back surface opposite from the front surface, the first semiconductor layer including a first section, a second section, and a trench laterally between the first section and the second section, the first semiconductor layer having a first conductivity type, the second semiconductor layer and the third semiconductor layer having a second conductivity type opposite from the first conductivity type, the first section of the first semiconductor layer adjoins a first portion of the second semiconductor layer, the second section of the first semiconductor layer adjoins a second portion of the second semiconductor layer, the trench has a trench bottom that is coextensive with a third portion of the second semiconductor layer, the first section of the first semiconductor layer is arranged between the first portion of the second semiconductor layer and the back surface, the second section of the first semiconductor layer is arranged between the second portion of the second semiconductor layer and the back surface, the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer are epitaxially grown on the bulk substrate, the bulk substrate comprises silicon carbide, the first semiconductor layer comprises silicon carbide, the second semiconductor layer comprises silicon carbide, and the third semiconductor layer comprises silicon carbide.