Modeling method for shield gate trench MOSFET

Abstract

The invention discloses a modeling method for a shield gate trench MOSFET, and the method comprises the steps: dividing a device structure into an intrinsic region, an electron diffusion region, a JFET region where a shield gate is located, and a lower region of the shield gate according to the device structure of the shield gate trench MOSFET; establishing physical models for the intrinsic region, the electron diffusion region, the JFET region where the shield gate is located and the lower region of the shield gate respectively; establishing a simulation model in a simulation circuit simulator according to the physical model; and judging whether the simulation model meets an error requirement or not so as to obtain the simulation model meeting the error requirement. Aiming at complex physical characteristics of a drift region and a substrate of the shield gate trench MOSFET, the drift region and the substrate are simply divided into three parts, including an electron diffusion region, a JFET region where a shield gate is located and a shield gate lower region; and establishing equivalent resistance models respectively for the divided areas, so that the simulation precision of direct current and alternating current is improved, and the model is ensured to accurately predict the I-V characteristics of the device.

Description

technical field [0001] The invention relates to the field of shielded gate trench MOSFETs, in particular to a modeling method for shielded gate trench MOSFETs. Background technique [0002] Shield Gate Trench MOSFET (SGT MOS) is a new type of vertical double-diffused metal oxide semiconductor field effect transistor (VDMOS), the structure of the shield gate can Reduce the on-resistance and gate charge of the device, and realize the low loss of the device. [0003] The model of a traditional VDMOS device is usually implemented using an intrinsic MOS series voltage-controlled resistor or a Junction Field-Effect Transistor (JFET), where the voltage-controlled resistor and the JFET device are used to simulate the I-V characteristics of the drift region. However, the traditional voltage-controlled resistance model is generally a multi-term expression of resistance with respect to voltage, which is only a simple fitting of the equivalent resistance in the drift region within a sp...

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Problems solved by technology

However, the traditional voltage-controlled resistance model is generally a multi-term expression of resistance with respect to voltage, which is only a simple fitting of the equivalent resistance in the drift region within a specific voltage range and cannot cover the entire voltage range; the JFET device model can only represent shielding The part of the drift region corresponding to the shield gate of the gate trench MOSFET, that is, the JFET region, is obviously unreasonable to use only the JFET device model to represent the entire drift region

[0004] In addition, unlike the pn junction control of JFET devices, the control structure of shielded gate trench MOSFET is a MOS structure, which is quite different from the JFET device model.

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