Field effect trench transistor having active trenches

A field effect trench transistor comprising:

• a multiplicity of trenches formed from a silicon surface of a semiconductor, said trenches running in parallel to one another and in a longitudinal direction parallel to the silicon surface of the semicondutor, including a plurality of stripe-shaped active trenches and a plurality of inactive trenches, which are adjacent to each other;
• and
• a multiplicity of transistor cells arranged as an array of the transistor cells having gate electrodes lying in the active trenches;
• wherein said plurality of inactive trenches lie within the array of the transistor cells and include no gate electrodes but a plurality of protecting means which are integrated in at least two inactive trenches of said inactive trenches, isolated by an oxide layer, connected in form of a series connection with one another in the longitudinal direction of each of the inactive trenches, and are contact connected at one end of the series connection of the protecting means to a gate metallization and at the opposite end of the series connection of the protecting means to a source metallization of said field effect trench transistor.

A field effect trench transistor comprising:

• a multiplicity of transistor cells arranged as an array of transistor cells;
• a plurality of stripe-shaped active and inactive trenches formed from a silicon surface of a semiconductor;
• wherein the active trenches and the inactive trenches run in parallel to one another and in a longitudinal direction parallel to the silicon surface of the semiconductor;
• wherein gate electrodes of said multiplicity of transistor cells lie in the active trenches;
• and
• wherein at least two inactive trenches of the plurality of stripe-shaped inactive trenches, which are adjacent to each other lie in the array of the transistor cells and includes no gate electrodes but a plurality of polysilicon protective diodes which are integrated in the at least two inactive trenches, isolated by an oxide layer, connected in form of a series connection with one another in the longitudinal direction of the at least two inactive trenches and are contact-connected at one end of the series connection of the plurality of polysilicon protective diodes to a gate metallization and at the opposite end of the series connection of the plurality of polysilicon protective diodes to a source metallization of the field effect trench transistor.