Field-effect transistor, and methods for production

A method for producing a field-effect transistor, comprising the following steps:

• providing a starting material including:
• a source layer doped according to a first type, a drain layer doped according to the first type, and a channel layer located vertically between the source layer doped according to the first type and the drain layer doped according to the first type;
• increasing a doping of the first type or reducing a doping of the second type in the channel layer in a doping region that is more than a specified distance from a gate region in which a gate trench is to be formed;
• and
• at least partially forming the gate trench in the gate region so that the gate trench extends vertically from the source layer doped according to the first type to the drain layer doped according to the first type and adjoins the channel layer.

A method for producing a field-effect transistor, comprising the following steps:

• providing a starting material including:
• a source layer doped according to a first type, a drain layer doped according to the first type and including a drift layer doped according to the first type and a spread layer doped according to the first type, a channel layer located vertically between the source layer doped according to the first type and the drain layer doped according to the first type, wherein the spread layer doped according to the first type is located vertically between the channel layer and the drift layer doped according to the first type, and has a higher doping of the first type than the drift layer doped according to the first type;
• at least partially forming a gate trench in a gate region so that the gate trench extends vertically from the source layer doped according to the first type to the drain layer doped according to the first type and adjoins the channel layer;
• and
• increasing a doping of a second type or reducing a doping of the first type in the channel layer in an intermediate region extending from the gate region to a specified distance, through implantation, into the gate trench.