Semiconductor device with trench field plate including first and second semiconductor materials

A semiconductor device comprising:

• a semiconductor body;
• a drift region of a first conductivity type;
• at least one trench extending into the drift region;
• at least one gate electrode;
• a field plate in at least a portion of the at least one trench, the field plate comprising a first semiconducting material that is at least partially of a second conductivity type, the second conductivity type that is complementary to the first conductivity type;
• and
• a dielectric material at least partially surrounding the gate electrode and the field plate;
• wherein the field plate further comprises a second semiconducting material of the first conductivity type, the second semiconducting material being arranged at least partially between the first semiconducting material and a contact region and adjacent to the contact region and comprising a doping concentration higher than a doping concentration of the first semiconducting material, and a diffusion barrier layer, the diffusion barrier layer being arranged at least partially between the first semiconducting material and the second semiconducting material.

A field effect transistor comprising:

• a semiconductor body;
• a drift region of a first conductivity type;
• at least one trench extending into the drift region;
• at least one gate electrode;
• a field plate in at least a portion of the at least one trench;
• and
• a dielectric material, wherein the dielectric material at least partially surrounds the gate electrode and the field plate;
• wherein the field plate comprises a first semiconducting material at least partially of a second conductivity type and a second semiconducting material of the first conductivity type, the second conductivity type being complementary to the first conductivity type, and a diffusion barrier layer arranged at least partially between the first semiconducting material and the second semiconducting material.

A method comprising:

• providing a semiconductor body, a drift region of a first conductivity type, at least one trench extending into the drift region, at least one gate electrode, and a field plate comprising a first semiconducting material in at least a portion of the at least one trench;
• depositing a dielectric material such that it at least partially surrounds the gate electrode and the field plate, wherein the field plate comprises the first semiconducting material at least partially of a second conductivity type and a second material of the first conductivity type, the second conductivity type being complementary to the first conductivity type;
• and
• arranging a diffusion barrier layer at least partially between the first semiconducting material and the second semiconducting material.