Separated gate CSTBT with self-biased PMOS and manufacturing method thereof

Abstract

The invention relates to a separated gate CSTBT with a self-biased PMOS and a manufacturing method of the separated gate CSTBT, and belongs to the technical field of power semiconductor devices. According to the present invention, on the basis of the traditional CSTBT, a separated gate electrode equipotential with the emitter and a P-type buried layer are introduced, the influence of an N-type charge storage layer on the breakdown characteristic of a device can be effectively shielded through charge compensation, and the compromise relation between the forward conduction voltage drop Vce (on) and the turn-off loss Eoff of the device can be improved. In addition, the separated gate electrode and a gate electrode are located in a same groove, so that the channel density can be reduced; the saturation current density is effectively reduced by turning on a parasitic PMOS to clamp the potential of the N-type charge storage layer, and the short-circuit safe working capability of the device is improved. Meanwhile, the gate capacitance can be reduced, the switching speed of the device is improved, and the switching loss of the device is reduced. In addition, the current uniformity in a chip can be improved, the current concentration is avoided, and the reliability and a reverse bias safety working area of the device are improved.

Description

technical field [0001] The invention belongs to the technical field of power semiconductor devices, and in particular relates to a split gate CSTBT with self-biased PMOS and a manufacturing method thereof. Background technique [0002] Insulated gate bipolar transistor (IGBT), as one of the core electronic components in modern power electronic circuits, is widely used in various fields such as transportation, communication, household appliances, and aerospace. The insulated gate bipolar transistor is a new type of power electronic device composed of an insulated field effect transistor (MOSFET) and a bipolar junction transistor (BJT), which can be equivalent to a MOSFET driven by a bipolar junction transistor. The IGBT combines the MOSFET structure and the working mechanism of the bipolar junction transistor. It not only has the advantages of easy driving, low input impedance, and fast switching speed of the MOSFET, but also has the advantages of large on-state current densi...

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Problems solved by technology

However, as the doping concentration of the N-type charge storage layer continues to increase, the breakdown voltage of the CSTBT device will decrease significantly, which limits the application of the device in the high-voltage field.

[0004] In the existing technology, in order to reduce the adverse effect of the N-type charge storage layer and obtain higher breakdown voltage and reliability, two methods are mainly adopted: (1) increasing the trench depth, usually, the trench depth is greater than The junction depth of the N-type charge storage layer; (2) reduce the trench gate pitch by refining the trench process, but the above method still has obvious defects: the implementation of method (1) will increase the gate capacitance, and the switch of the IGBT The essence of the process is the process of charging and discharging the gate capacitance, so the increase of the gate capacitance will reduce the switching speed of the device, which in turn will increase the turn-off loss of the device.

On the one hand, the implementation of method (2) will increase the gate capacitance of the device, resulting in an increase in the turn-off loss of the device; on the other hand, the excessive MOS channel density will also increase the saturation current density of the device, so that the Short circuit safe operating area (SCSOA) deterioration

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