Preparation method of high-quality scandium-doped aluminum nitride film template

Abstract

The invention provides a preparation method of a high-quality scandium-doped aluminum nitride film template. The preparation method includes the following steps of: S1, preparing a substrate; S2, depositing a film transition layer on the substrate by adopting a coating technology; S3, thermally treating the film transition layer at a high temperature in a pure nitrogen atmosphere by adopting a high-temperature face-to-face heat treatment technology to form a high-quality buffer layer; and S4, depositing a scandium-doped aluminum nitride film on the buffer layer by adopting a reactive magnetron sputtering deposition method. The preparation method provided by the invention can be used for preparing a scandium-doped aluminum nitride thin film with a high crystallization property, solves the problem that the orientation of the aluminum nitride thin film is seriously deteriorated due to doping of a high Sc concentration, and achieve results of far exceeding the level of the prior art under different film thicknesses, and lays a solid foundation for application of SAW / BAW devices with a higher frequency, enhanced piezoelectric response, a higher electromechanical coupling coefficient and a higher Q value.

Description

technical field [0001] The invention relates to the technical field of semiconductor material preparation, in particular to a method for preparing a high-quality scandium-doped aluminum nitride film template. Background technique [0002] Aluminum nitride (AlN) is a hexagonal wurtzite structure III-V nitride widely used in the field of acoustic wave electronic devices. Compatible and has high thermal conductivity. In addition, due to its own characteristics such as high surface acoustic wave (SAW) phase velocity and low material temperature coefficient (TCD), aluminum nitride thin films have achieved rapid development in the past 30 years. However, due to the relatively small lateral effective electromechanical coupling coefficient (≈0.5%) of AlN thin film, its application is limited. In order to improve its electromechanical coupling coefficient while retaining other excellent properties, an effective method is to dope it to produce a new ternary nitride, and use other Gr...

AI Technical Summary

Problems solved by technology

[0004] Although SAW / BAW devices based on scandium-doped aluminum nitride thin films have very bright application prospects, there are great difficulties and challenges in the preparation of scandium-doped thin films, and it is difficult to achieve high-quality and mass production

Currently, based on the low aluminum phase (La 3 Ga 5.5 Ta 14 o 14 , LGT), silicate (La 3 Ga 5.5 Ta 0.5 o 14 , LGT) or aluminosilicate (La 3 Ga 5.5 Nb 0.5 o 14 , LGN) commercially available SAW devices have low phase velocity (eg LGS: 2700m / s) and high acoustic propagation loss, with the increase of temperature and frequency, the acoustic loss will increase greatly

In addition, since the layered wurtzite structure is not the most stable phase, as the doping concentration of scandium increases, the coating process parameter window will narrow, and the orientation of the film will easily deteriorate or even form a polycrystalline film, resulting in a decrease in the pressure of the film. Electrical performance, which brings deterioration of the electromechanical coupling coefficient and quality factor Q value to the device

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