Vertical field effect transistor with algan/gan heterojunction and its manufacturing method

Abstract

The invention provides a vertical field effect transistor with AlGaN / GaN heterojunction and a manufacturing method thereof. The device has two characteristics: one is that the two-dimensional electron gas formed by the AlGaN / GaN heterojunction is used to form a lateral low-resistance conductive channel of the device; the other is that a vertical low-resistance conductive channel is introduced in the drift region of the device. When the device is turned off, due to the introduction of new charges by the two-dimensional electron gas, the electric field distribution in the device is changed, the breakdown voltage is increased, and the contradictory relationship between the breakdown voltage and the concentration of the drift region is alleviated. When the device is turned on, since the new conductive channel changes the current distribution of the traditional vertical field effect transistor, a lower on-resistance can be achieved even when the concentration of the drift region is lower. Combining the above advantages, the present invention has higher withstand voltage and lower conduction loss under the condition of the same drift region length.

Description

technical field [0001] The invention relates to the field of power semiconductor devices, in particular to a vertical field effect transistor with an AlGaN / GaN heterojunction. Background technique [0002] Power semiconductor devices refer to high-power electronic devices mainly used in power conversion and control circuits of power equipment. As an important component in the field of power semiconductor devices, the vertical double-diffused metal oxide semiconductor has fast switching speed, low loss, high input impedance, low driving power, good frequency characteristics, and highly linear transconductance. It has been widely used in power integrated circuits and power integrated systems. [0003] As one of the cores of third-generation semiconductor materials, GaN material is special in that it has a polarization effect compared with Si, GaAs and silicon carbide (SiC). The AlGaN / GaN heterojunction forms a high-density two-dimensional electron gas (two dimensional electr...

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Problems solved by technology

[0004] At present, devices based on GaN materials are mainly lateral HEMT devices. Common AlGaN / GaN HEMTs devices have a large leakage current due to the Schottky contact of the gate. The high electric field peak on the device surface will also bring a series of hot electrons. Injection, inverse piezoelectric effect, etc., have adverse effects on the performance of the device. In addition, the lateral device still has a smaller current density than the vertical device. However, because the two-dimensional electron gas density is affected by the interface characteristics and crystal orientation, Difficult to apply to traditional vertical devices

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