MOS-transistor structure with a trench-gate-electrode and a limited specific turn-on resistance and method for producing an MOS-transistor structure

A method for fabricating a MOS transistor structure, which comprises:

• providing a highly doped substrate layer of a first conduction type;
• epitaxially growing a body layer of a second conduction type on the highly doped substrate layer;
• forming a source region in the body layer;
• patterning a trench in the body layer such that the trench adjoins the source region and has a bottom;
• implanting doping material of the first conduction type through the bottom of the trench into the body layer to produce a drift region extending from the bottom of the trench as far as the highly doped substrate layer;
• before or after performing the step of implanting the doping material, forming a gate oxide layer that lines the trench;
• and
• filling the trench with a gate electrode.

A method for fabricating a MOS transistor structure, which comprises:

• providing a highly doped substrate layer of a first conduction type;
• growing a sequence of doped, epitaxial partial layers of a given conduction type on the highly doped substrate layer;
• after each process of growing one of the partial layers, producing doped regions in the one of the partial layers such that the sequentially produced doped regions and the sequentially produced partial layers together define pillar-type structured body regions and pillar-type structured drift regions;
• producing the doped regions to have a conduction type opposite that of the given conduction type of the partial layers;
• forming source regions in the body regions;
• patterning trenches in the drift regions and producing the trenches to adjoin at least one of the body regions and at least one of the source regions;
• lining the trenches with a gate oxide layer;
• and
• filling the trenches with a gate electrode.

A method for fabricating a MOS transistor structure, which comprises:

• providing a highly doped substrate layer of a first conduction type;
• providing a body layer of a second conduction type on the highly doped substrate layer;
• forming trenches in the body layer;
• filling the trenches with doped semiconductor material of the first conduction type;
• etching back the doped semiconductor material as far as the body layer so that drift regions of the first conduction type and body regions of the second conduction type define a surface;
• forming source regions in the body regions;
• patterning trenches into the drift regions such that each one of the trenches adjoins at least one of the body regions and one of the source regions;
• lining the trenches with a gate oxide layer;
• and
• filling the trenches with a gate electrode.