Preparation method of aluminum nitride monocrystalline film

Abstract

The invention belongs to the technical field of semiconductor film materials, and particularly discloses a preparation method of an aluminum nitride (AlN) monocrystalline film. The method comprises the steps of utilizing a ZnO monocrystalline substrate or other heterogeneous materials as a substrate, growing an AlN film by using an atomic layer deposition coating (ALD) method, putting the cleaned substrate into a reaction chamber and setting the temperature of the reaction chamber to be 250-500 DEG C; utilizing trimethylaluminum (TMA), an ammonia gas (NH3) and the like as reaction precursors and alternately introducing the reaction precursors for growing the AlN film; and finally forming the AlN monocrystalline film in a nonpolar direction (100) through epitaxial growth. According to the preparation method of the aluminum nitride monocrystalline film, epitaxial growth of the AlN material is achieved under a low temperature condition; the growth temperature and the requirements on the vacuum degree are greatly reduced; the process is simple; the growth cost of AlN monocrystalline is reduced; and the preparation method is compatible with an existing semiconductor growth technology. The preparation method of the aluminum nitride monocrystalline film has a wide application prospect in the aspects of an AlN-based deep ultraviolet light-emitting device, a piezoelectric device, a surface, buffer layers of a bulk acoustic wave device, a field emission device and an III-IV nitride device and the like.

Description

technical field [0001] The invention belongs to the technical field of semiconductor thin film materials, in particular to a method for epitaxially growing single crystal aluminum nitride (AlN) thin films on ZnO single wafers or heterogeneous substrates under low temperature conditions. [0002] technical background [0003] AlN is a kind of III-IV nitride material, it has extremely high bandgap width (6.2 eV), excellent piezoelectric response, good heat conduction and thermal stability, very low electron affinity, in the deep Ultraviolet light-emitting diodes, surface and bulk acoustic wave devices, piezoelectric devices, field emission devices, buffer layers of III-IV nitride devices, etc. have great application potential. Compared with polycrystalline structures, AlN single crystal materials have fewer defects and lower interface state density, so the performance of devices based on single crystal AlN is much stronger than that of amorphous or polycrystalline AlN-based dev...

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Problems solved by technology

However, some of these growth methods require extremely high growth temperatures, and some require extremely high vacuum degrees. For example, the temperatures required to grow AlN single crystal films by MOCVD and MBE methods are all at 700 o C above, and the background pressure of growing single crystal AlN film by PLD method is required to be 10 -10 Torr magnitude, which shows that these methods require great energy and cost to grow AlN single crystal

However, ALD technology can grow thin films at lower temperature and low vacuum conditions. Because it is a self-limiting surface reaction, it can precisely control the thickness of the film. In the past, AlN thin films grown by ALD technology were polycrystalline or amorphous. Epitaxial growth of single crystal AlN thin films by ALD technology has never been reported in the literature

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