Semiconductor device including trench gate structure and buried shielding region and method of manufacturing

A semiconductor device, comprising:

• a trench gate structure extending from a first surface into a silicon carbide body and comprising a first sidewall and an opposite second sidewall;
• a top shielding region extending along the second sidewall from the first surface into the silicon carbide body;
• and
• a buried shielding region extending along a bottom area of the trench gate structure, wherein:
• the buried shielding region and the top shielding region are connected;
• and
• a lateral edge of the buried shielding region oriented to the top shielding region is at least one of below the trench gate structure or below the top shielding region,
• wherein at least one of:
• the bottom area of the trench gate structure comprises a local recess;
• or
• in a horizontal plane at half of a vertical extension of the top shielding region, a dopant concentration in the top shielding region has a maximum at the second sidewall of the trench gate structure.

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

• implanting first dopants through a first surface section, exposed by an implant mask opening, of a first surface of a silicon carbide body;
• forming a trench extending from the first surface, through which the first dopants were implanted, into the silicon carbide body, wherein the trench comprises a first sidewall surface and an opposite second sidewall surface;
• forming a spacer mask covering at least the first sidewall surface;
• implanting second dopants through a portion of a bottom surface of the trench exposed by the spacer mask, wherein the first dopants and the second dopants have a same conductivity type;
• and
• activating the first dopants and the second dopants, wherein:
• the first dopants form a doped top shielding region adjoining the second sidewall surface;
• and
• the second dopants form a doped buried shielding region adjoining the bottom surface,
• at least one of:
• wherein:
• at least a portion of the second dopants are implanted with an implantation beam axis tilted with respect to a vertical direction at an implant angle in a vertical plane orthogonal to a horizontal longitudinal extension of the trench;
• and
• the implantation beam axis is directed to the second sidewall surface;
• wherein forming the spacer mask comprises exposing and recessing a portion of the bottom surface of the trench;
• or
• wherein forming the spacer mask comprises:
• forming an auxiliary mask layer filling the trench and covering the first surface;
• and
• selectively removing a first auxiliary mask layer portion that adjoins the second sidewall surface, wherein a residual second auxiliary mask layer portion covering at least the first sidewall surface forms the spacer mask.