C-axis vertical preferred orientation AlN piezoelectric film and preparation method thereof

Abstract

The invention relates to the technical field of thin film material preparation, in particular to a C-axis vertical preferred orientation AlN piezoelectric thin film and a preparation method thereof, and the preparation method comprises the step: a self-buffer layer AlN thin film, a metal electrode layer and an AlN piezoelectric thin film are sequentially prepared on a sapphire or YAG crystal. Andthe self-buffer layer AlN film induces the orientation of the metal electrode layer, so that the highly C-axis preferred orientation AlN film is prepared on the electrode layer. The sapphire or YAG crystal and the high-purity sputtering target form an angle of 45 degrees, so that the energy of migration motion parallel to the surface of the substrate after sputtering atomic groups reach the substrate is effectively regulated and controlled, the growth of a buffer layer and the C-axis preferred orientation growth of the AlN piezoelectric film are facilitated, and the piezoelectric response andelectromechanical coupling coefficient of the film are improved. According to the method disclosed by the invention, the C-axis preferred orientation AlN film can be grown by utilizing a magnetron sputtering technology at a relatively low temperature, and the obtained AlN film is high in crystallinity and has a relatively high piezoelectric response coefficient and a relatively high electromechanical coupling coefficient.

Description

technical field [0001] The invention relates to the technical field of thin film material preparation, in particular to a C-axis vertical preferred orientation AlN piezoelectric thin film and a preparation method thereof. Background technique [0002] Bulk acoustic wave (BAW) devices are mainly used in radio communication and radar systems, mainly including BAW delay lines, BAW resonators, BAW filters, etc. Among them, thin-film BAW delay lines (BAWDL) have developed rapidly in research and application in recent years. A type of very high frequency device, which has the advantages of small size, light weight, and no edge in the microwave frequency band, and has been widely used in systems such as airborne and missile-borne wireless altimeters. [0003] Traditional BAWDL often uses zinc oxide (ZnO) film, ZnO is an amphoteric oxide, can react with acid and alkali, and is sensitive to ambient humidity, and in the preparation process, the oxygen vacancies of ZnO film are difficu...

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Problems solved by technology

Although the traditional magnetron sputtering process can prepare AlN thin films, the horizontal motion energy of the sputtered particles reaching the substrate surface is low, the surface roughness of th...

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