Longitudinal high voltage power semiconductor device structure with low relative dielectric constant buried layer

Abstract

The invention discloses a longitudinal high-voltage power semiconductor device structure with a low relative dielectric constant buried layer. The semiconductor device structure comprises an N drift region, a P base region and an N+ source region, wherein a gate oxide layer is deposited in a trench at the periphery of the P base region and the N+ source region, and a gate conductive dielectric layer is deposited on the gate oxide layer. The semiconductor device structure is characterized in that an insulating layer is additionally arranged in the N+ drift region below the gate oxide layer; theinsulating layer is made of an insulating material of which the relative dielectric constant is less than that of the gate oxide layer; and the material of the device is Si, SiC or GaN. By additionally arranging the insulating layer with a certain thickness below the trench, the electric field distribution between the gate and the drain can be adjusted, so that the electric field distribution ofthe internal region of the device is changed, the withstand voltage of the device is also improved, and the electric field distribution in the device is not only limited by the doping concentration ofa material any more.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a semiconductor device structure for increasing withstand voltage and reducing on-resistance in vertical power semiconductor devices. Background technique [0002] Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is a field-effect transistor that can be widely used in analog circuits and digital circuits. It is a two-layer pn junction structure of npn or pnp. A gate electrode formed of an oxide layer and a conductive material is loaded on the middle semiconductor layer. The gate electrode can control the turn-on and turn-off of the MOS device, thereby realizing the circuit control. Because of its infinite gate input impedance (isolation of the gate oxide layer), MOS devices are more power-saving and easier to drive. They are not only widely used in digital signal processing occasions such as microprocessors and microcontrollers, but also more and more Ground...

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Problems solved by technology

However, it does not significantly improve the maximum electric field in the device where the CC' channel is close to the edge of the trench, that is, the position where the device is most prone to breakdown still exists

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