Trench gate charge storage type IGBT and manufacturing method thereof

Abstract

The invention discloses a trench gate charge storage type IGBT, and belongs to the technical field of semiconductor power devices. A conventional trench gate structure is widened, and a side wall gateelectrode structure is employed for forming a mesa structure located below a base region. moreover, a shielding trench structure for shielding the electric field of a charge storage layer is introduced, thereby improving the carrier injection enhancement effect, and improving the compromise between a forwarding ON voltage drop Vceon and the OFF loss Eoff. The electric field concentration effect at the tip of the bottom of a trench is alleviated, and the breakdown voltage of a device is effectively improved. The gate capacitance of the device, especially the Miller capacitance CGC and the gatecharge QG, is reduced, the switching speed of the device is improved, the switching loss of the device is reduced, and the requirements for the capability of a gate drive circuit are reduced. The constraint on the doping concentration of an N-type charge storage layer and the withstand voltage of the device from the thickness are avoided, the saturation current density is reduced, and a short-circuit safe operating region (SCSOA) of the device is improved. Moreover, an EMI effect is effectively inhibited when the device is turned on. In addition, the manufacturing method is compatible with aconventional trench gate charge storage type IGBT manufacturing method.

Description

technical field [0001] The invention belongs to the technical field of power semiconductor devices, in particular to a trench gate charge storage type insulated gate bipolar transistor (CSTBT). Background technique [0002] Insulated Gate Bipolar Transistor (IGBT) was proposed on the basis of research on power MOSFET, BJT and SCR / GTO, etc. In the late 1970s and early 1980s, it was invented by introducing a PN junction into the back substrate of the power MOSFET structure and achieve mass production. The conductance modulation effect introduced by the PN junction on the back of the device when the device is turned on makes the IGBT a new type of power electronic device that is composed of a MOS field effect transistor and a bipolar junction transistor (BJT), and can also be equivalent to a bipolar junction transistor (BJT). ) driven MOSFET structure. IGBT combines the characteristics of both MOSFET and BJT: not only has the advantages of high input impedance, low control po...

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Problems solved by technology

[0006] The implementation of method (1) will increase the gate-emitter capacitance and gate-collector capacitance at the same time, and the switching process of the IGBT is essentially the process of charging/discharging the gate capacitance, so the increase in the gate capacitance will Makes the charging/discharging time longer, which in turn causes the switching speed to decrease

Therefore, the deep trench gate depth will reduce the switching speed of the device, increase the switching loss of the device, and affect the compromise characteristics of the device's conduction voltage drop and switching loss; and the implementation of method (2) will increase the device's switching loss The gate capacitance will reduce the switching speed of the device and increase the switching loss, which will affect the compromise be

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