Self-biased split-gate trench power mosfet device

Abstract

The present invention relates to the field of power semiconductor devices, in particular to a split gate trench type MOS device, specifically a self-biased split gate trench type power MOSFET device; the present invention introduces self-bias on the basis of a traditional split gate trench type MOS device The voltage structure uses the gate control signal to provide self-bias voltage to the split gate. Compared with the traditional split gate trench MOS device, due to the effect of self-bias voltage, an accumulation layer is generated when the device is turned on, so that the device's The ratio of on-resistance is greatly reduced. In this specification, the realization of the split gate self-bias voltage is divided into two ways, namely adding an external circuit and adding a structure that can provide a bias voltage. The bias voltage of the former comes from the drive circuit of the gate. Compared with the former , the latter has the advantage of reducing drive power consumption.

Description

technical field [0001] The invention relates to the field of power semiconductor devices, in particular to a split gate trench type MOS device, in particular to a self-biased split gate trench type power MOSFET device. Background technique [0002] The introduction of the split gate makes the capacitance C between the gate and drain of the trench power MOS device GD , The switching loss is significantly reduced, which effectively increases the operating frequency of the device. However, in the traditional split gate trench MOS device structure, the split gate is usually connected to the source electrode S, which increases the specific conduction of the device to a certain extent. resistance, such as figure 1 shown. In order to reduce the specific on-resistance of the split-gate trench MOS device, in the design process of the split-gate trench MOS device, a high potential relative to the source electrode S can be applied to the split gate SG to prevent oxidation of the spli...

AI Technical Summary

Problems solved by technology

In order to reduce the specific on-resistance of the split-gate trench MOS device, in the design process of the split-gate trench MOS device, a high potential relative to the source electrode S can be applied to the split gate SG to prevent oxidation of the split gate Layer sidewalls form an accumulation layer, thereby reducing the specific on-resistance of the device, such as figure 2 shown; but the device will change from the original three-terminal device to a four-terminal device, which is not conducive to compatibility with conventional devices. At the same time, it provides bias for the split gate SG, which requires an additional power supply, which increases the complexity and cost of the application.

Images