Transistor device and method for forming a recess for a trench gate electrode

Abstract

The invention discloses a transistor device and a method for forming a recess for a trench gate electrode. In an embodiment, a method of forming a recess for a trench gate electrode comprises forminga trench in a first major surface of a semiconductor substrate, the trench having a base and a side wall extending from the base to the first major surface, forming a first insulating layer on the base and the side wall of the trench, inserting a first conductive material into the trench that at least partially covers the first insulation layer to form a field plate in a lower portion of the trench, applying a second insulating layer to the first major surface and the trench such that the second insulating layer fills the trench and covers the conductive material, removing the second insulating layer from the first major surface and partially removing the second insulating layer from the trench by wet chemical etching and forming a recess for a gate electrode in the second insulating layerin the trench.

Description

Background technique [0001] Many functions of modern devices in automotive, consumer and industrial applications, such as controlling electric motors or electric machines, are based on semiconductor transistor devices such as field effect transistors such as MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) and IGBTs (Insulated Gate Dual pole transistor)). [0002] The capacitance between the gate electrode and the supply electrodes—the source and drain electrodes for MOSFETs and the emitter and collector electrodes for IGBTs—and the blocking voltage of the transistors can be determined by Operating parameters optimized to improve performance of transistor devices. Buried field plates can be used to increase the on-resistance R for a specific on the blocking voltage. The field plate and the gate electrode may be arranged in the trench, wherein the field plate is arranged towards the bottom of the trench and the gate electrode is arranged towards the top of the tr...

AI Technical Summary

Problems solved by technology

Although a buried field plate can be used to reduce the gate-to-drain capacitance (Qgd), a capacitance is created between the gate electrode and the field plate which forms part of the gate-to-source capacitance (Qgs) because the field plate is typically coupled to source potential

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