Carrier-storing grooved gate IGBT with P-type floating layer

Abstract

The invention relates to a carrier-storing grooved gate IGBT with a P-type floating layer, belonging to the technical field of semiconductor power devices. On a basis of the prior carrier-storing grooved gate bipolar transistor, a P-type floating layer (13) is introduced to almost free a carrier-storing layer from bearing a withstanding voltage and decrease a forward conducted voltage drop; and the P-type floating layer (13) also improves the electric-field integration effect of the bottom of the grooved gate, thereby effectively decreasing an electric filed with a maximum peak value, preventing the bottom of the grooved gate and the vicinity of the high-concentration carrier-storing layer from being broken down by an overhigh electric field and greatly increasing the breakdown voltage ofthe device. A JFET zone is introduced due to the existence of the P-type floating layer. When the device is forwardly conducted, the resistance of the JFET zone continuously increases along with the continuously increasing voltage of a collector so that the saturation current of the device is decreased, and a lower conducted voltage drop is obtained while maintaining a greater short-circuit safety operation area (SCSOA).

Description

technical field [0001] A carrier storage slot gate IGBT structure with a P-type floating layer belongs to the technical field of semiconductor power devices. Background technique [0002] Insulated gate bipolar transistor is a rapidly developing and widely used power electronic device. It is a new device combined with the advantages of high input impedance of MOSFET, simple driving circuit, high current density and low saturation voltage of bipolar transistor. Now it is widely used in induction cooker, UPS uninterruptible power supply, automotive electronic igniter, frequency converter, motor transmission system and other energy conversion devices. [0003] IGBT was first proposed in 1982 as a punch-through structure, such as figure 1 As shown, it is at high concentrations of P + N-type buffer layer 3, N-type buffer layer 3, N - The base region layer 4 is fabricated into an insulated gate bipolar transistor structure. Due to the presence of the N-type buffer layer 3, th...

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Problems solved by technology

However, the saturation current of the device is also greatly increased at the same time, and the short-circuit safe operating area (SCSOA) is reduced. In order to improve this phenomenon, the cell of the carrier storage tank-gate bipolar transistor is usually larger than that of the trench-gate insulated gate bipolar transistor. The cell of the n-type transistor is small, and the concentration and thickness of the n-type carrier storage layer 12 will also be limited, thereby limiting the reduction of the forward voltage drop

In addition, the electric field concentration at the sharp corner of the trench gate reduces the breakdown voltage of the device

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