HEMT epitaxial structure with low buffer layer leakage current and HEMT device

Abstract

The invention discloses an HEMT epitaxial structure with low buffer layer leakage current. The HEMT epitaxial structure comprises a silicon substrate, an AlN nucleating layer, a back barrier electron barrier layer, a stress regulation and control layer, a GaN high-resistance layer, a GaN channel layer and a barrier layer which are sequentially arranged from bottom to top, the silicon substrate comprises a first sub-substrate, a second sub-substrate and a third sub-substrate which are sequentially arranged from bottom to top; and the back barrier electron barrier layer is of a periodically epitaxial Al < x > Ga < 1-x > N / Al < y > Ga < 1-y > N superlattice structure. The invention also provides an HEMT device with low buffer layer leakage current. According to the invention, the first sub-substrate and the second sub-substrate are contacted to form a PN junction, and an inversion electron layer is prevented from being formed on the interface of the silicon substrate and the AlN nucleating layer, so that electrons of the silicon substrate are prevented from entering the stress regulation and control layer, and the electric leakage of the buffer layer is reduced. Meanwhile, the back barrier electron barrier layer with the superlattice structure can effectively improve the barrier between the interface of the AlN / Si substrate and the stress regulation and control layer, prevents substrate electrons from being injected into the stress regulation and control layer, and reduces the electric leakage of the stress regulation and control layer.

Description

technical field [0001] The invention belongs to the technical field of nitride electronic devices, in particular to a HEMT epitaxial structure with low buffer layer leakage current and a HEMT device. Background technique [0002] In recent years, the electronic transformation of almost the whole industry has greatly increased the social demand for electronic power devices. Since the invention of the first GaN-based electronic device, the high electron mobility transistor (HEMT) with AlGaN / GaN heterojunction as the core has developed rapidly in the past two decades. However, the current GaN-based electronic device is expensive and the market space Small, large-size silicon substrate can greatly reduce the cost, but the huge lattice mismatch and thermal expansion coefficient difference between Si and GaN will cause the subsequent epitaxial layer to bear huge tensile stress, which will cause high-density dislocations. Some dislocations even run through the entire epitaxial lay...

AI Technical Summary

Problems solved by technology

The current method to improve the performance of silicon-based HEMT devices is to increase the thickness of the GaN buffer layer on the substrate, but this method is difficult to control, with low yield and high cost

Moreover, the silicon substrate that is not completely insulated will provide electrons to the buffer layer, and the substrate electrons entering the buffer layer will increase the leakage current of the buffer layer, resulting in a high leakage current in the buffer layer of silicon-based HEMT devices, which is prone to breakdown, resulting in device damage

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