Device structure for reducing current collapse of GaN power switching device

Abstract

The present invention provides a device structure for reducing the current collapse of a GaN power switching device. The structure comprises a Si substrate, a GaN buffer layer, a GaN channel layer, an intrinsic AlGaN layer, a mask dielectric layer, an insulating gate dielectric layer, source, drain and gate metal layers, and a Mg injection layer. An AlGaN / GaN heterostructure is epitaxially grown on the substrate to form a two-dimensional electron gas conductive channel, and the enhanced GaNMOS is realized by etching a passivation layer and the intrinsic AlGaN layer below the gate region. A P-type layer formed at the source end is connected with the GaN buffer layer by injecting Mg ions, and the p-type layer can provide a large number of holes to the GaN buffer layer in a short time and shorten the recovery time of the GaN buffer layer when the device is switched from the off state to the open state, thus greatly reducing the on-resistance. The structure provided by the invention effectively reduces the current collapse caused by the defects of the GaN buffer layer, improves the device switching speed, and significantly optimizes the electrical performance of the GaN power device.

Description

Technical field [0001] The invention belongs to the field of semiconductor technology and relates to the structure and manufacturing process of a GaN-based power electronic device Background technique [0002] As a representative of the third-generation semiconductor, GaN has the advantages of large forbidden band width, high saturation drift speed, high critical breakdown field strength, high thermal conductivity, etc., especially when the GaN heterostructure is not doped, it can be achieved by strong spontaneous polarization effect It produces high-concentration two-dimensional electron gas, and its superior performance makes it widely used in power electronics, radio frequency microwave and other fields. [0003] The reliability problem represented by current collapse is one of the most serious problems for GaN-based power switching devices to finally move toward practical use. The current collapse causes the dynamic resistance of the device to decrease, which increases the dyn...

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Problems solved by technology

[0005] At present, the method of reducing the current collapse of GaN power devices is mainly achieved by weakening the influence of surface or barrier layer traps on channel electrons. In widely used GaN power devices, the GaN buffer layer is often doped with a certain concentration of C, Fe and other elements to improve the withstand voltage level of the device, but this often introduces a considerable number of defects in the GaN buffer layer, and these defects will also cause current collapse to a certain extent, and the current collapse caused by the GaN buffer layer has not been well resolved. measure

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