Heteroepitaxial film structure

Abstract

The invention relates to an epitaxial film structure. The epitaxial film structure comprises a substrate, an epitaxial layer and a buffer layer, wherein the substrate is a gallium nitride substrate having an epitaxial growth surface; the epitaxial layer is an oxide film having dielectric tunability, and the film grows on the epitaxial growth surface of the substrate; the buffer layer is arranged between the substrate and the epitaxial layer; the buffer layer is formed by two layers of oxide films.

Description

technical field [0001] The invention relates to a heterogeneous epitaxial thin film structure, in particular to a dielectric adjustable thin film epitaxial thin film structure on a gallium nitride substrate. Background technique [0002] Bismuth-based cubic pyrochlore structure dielectric materials have broad application prospects in high-Q microwave voltage-controlled devices. At the same time, due to its high dielectric constant and low loss characteristics under microwave, it can also be used in the gate dielectric film of gallium nitride high electron mobility transistors, reducing the direct tunneling effect and the electric field strength of the gate dielectric layer. If it can be integrated with gallium nitride, it will promote the multi-functional integration and miniaturization of monolithic microwave integrated circuits, and improve system reliability. [0003] The existing technologies mainly include: (1) using physical film growth methods such as magnetron sputt...

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Problems solved by technology

However, due to the crystal structure of the GaN substrate and the cubic pyrochlore structure Bi with dielectrically tunable properties 1.5 ZnNb 1.5 o 7 or Bi 1.5 MgNb 1.5 o 7 The crystal structure of the material is quite different, and the existing technology is mainly to obtain the polycrystalline structure of Bi 1.5 ZnNb 1.5 o 7 or Bi 1.5 MgNb 1.5 o 7 film, and the quality and orientation of film growth are controlled by process conditions, and the cubic pyrochlore structure Bi on the GaN substrate cannot be obtained 1.5 ZnNb 1.5 o 7 or Bi 1.5 MgNb 1.5 o 7 Epitaxial film

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