Semiconductor device comprising a trench structure

A semiconductor device, comprising:

• a trench structure extending into a semiconductor body from a first surface, the trench structure comprising a shield electrode, a dielectric structure and a diode structure,
• a gate trench structure extending into the semiconductor body, the gate trench structure comprising a gate electrode of a transistor structure that is configured to control a load current between source and drain regions that are disposed in the semiconductor body,
• an electrically insulating isolation layer formed on the first surface of the semiconductor body,
• a source contact structure formed on the electrically insulating isolation layer in a first lateral region and electrically connected to the source region,
• a gate contact structure formed on the electrically insulating isolation layer in a second lateral region and electrically connected to the gate electrode,
• a lateral gap between the source and gate contact structures,
• wherein the trench structure comprises a first end that is directly below the source contact structure, a second end that is directly below the gate contact structure, and a middle region that is directly below the lateral gap,
• wherein a first terminal of the diode structure is electrically connected to the source contact structure by a first electric contact structure that extends through the isolation layer and directly contacts the first end and the source contact,
• wherein a second terminal of the diode structure is electrically connected to the gate contact structure by a second electric contact structure that extends through the isolation layer and directly contacts the second end and the gate contact,
• wherein the diode structure comprises a polycrystalline silicon layer having first regions and at least one second region of opposite conductivity type alternately arranged to form a back-to-back diode chain in the trench structure,
• wherein the polycrystalline silicon layer is spaced apart from the shield electrode by the dielectric structure,
• wherein the shield electrode is disposed below the diode structure and electrically isolated from the semiconductor body by the dielectric structure.

A method for manufacturing a semiconductor device, the method comprising:

• forming a trench structure extending into a semiconductor body from a first surface;
• and
• forming, in the trench structure, a shield electrode, a dielectric structure, and a diode structure,
• forming a gate trench structure extending into the semiconductor body, the gate trench structure comprising a gate electrode of a transistor structure that is configured to control a load current between source and drain regions that are disposed in the semiconductor body,
• forming an electrically insulating isolation layer formed on the first surface of the semiconductor body,
• forming a source contact structure on the electrically insulating isolation layer in a first lateral region and electrically connected to the source region,
• forming a gate contact structure on the electrically insulating isolation layer in a second lateral region and electrically connected to the gate electrode,
• forming a lateral gap between the source and gate contact structures,
• wherein the trench structure comprises a first end that is directly below the source contact structure, a second end that is directly below the gate contact structure, and a middle region that is directly below the lateral gap,
• wherein a first terminal of the diode structure is electrically connected to the source contact structure by a first electric contact structure that extends through the isolation layer and directly contacts the first end and the source contact,
• wherein a second terminal of the diode structure is electrically connected to the gate contact structure by a second electric contact structure that extends through the isolation layer and directly contacts the second end and the gate contact,
• wherein the diode structure is arranged at least partly between the first surface and a first part of the dielectric structure,
• wherein the shield electrode is arranged between the first part of the dielectric structure and a bottom of the trench structure,
• wherein the shield electrode and the semiconductor body are electrically isolated by the dielectric structure.