The diamond wafer in piezoelectric materials

With the advent of 5G massive data, it is critical to improve the frequency and bandwidth of surface acoustic wave devices. In this work, ZnO, AlN, and LiNbO3 piezoelectric materials were applied to a three-layer structure based on the diamond as the substrate. Unlike conventional structures, the widths of two piezoelectric materials are different. The electromechanical coupling coefficient based on the ZnO/ZnO/diamond structure can be remarkably improved to 8.26%, while a high frequency of 2 GHz can also be obtained. The structure based on the AlN/AlN/diamond structure is more inclined to obtain a high frequency of 3.76 GHz and an electromechanical coupling coefficient of 4.64%. Rational selection of piezoelectric materials and film thickness of surface acoustic wave devices can achieve different degrees of enhancement of electromechanical coupling coefficients and frequency. Finally, it was found that the larger electric potential on the surface of the diamond will result in a larger electromechanical coupling coefficient when the first layer of piezoelectric material is identical.

The acceleration of integration has raised the standard of people's lives. Surface acoustic wave (SAW) devices are widely used in radar communication, sensors, filters, and microfluidics due to their low propagation speed, short wavelength, good repeatability, and high resistance to radiation. With the advent of the 5G era, the increase of data transferred has forced us to face the question of how to boost the bandwidth and frequency of SAW devices. The electromechanical coupling coefficient (k2) is a parameter that represents the conversion efficiency of mechanical and electrical energy in piezoelectric materials, and its magnitude determines the bandwidth of the SAW device. This means that the larger k2 can transfer more data. Therefore, it is imperative to improve k2 to meet the needs of people.

To further increase the frequency and electromechanical coupling coefficient of the device, the traditional POI structure is improved. Firstly, the effect of different piezoelectric materials and film thicknesses on the frequency of the device is investigated. The results show that the electromechanical coupling coefficient increases significantly with the increase of frequency. In the "Tree shape" structure, a large electromechanical coupling coefficient of 8.26% and a high frequency of 3.4 GHz can be achieved. To explore the relationship between the electromechanical coupling coefficient and the electric potential, the electric potential generated by different structures is shown. The structural arrangement that excited the electric potential from largest to smallest is the same as the arrangement of the structure that achieved the maximum k2. Finally, we found that a larger electric potential on the surface of the diamond will result in a larger k2 when the first layer of piezoelectric material is identical.

CSMH firstly innovated the technology of diamond-based AlN with XRD (0002) rocking curve <3°, ultra-high thermal conductivity of diamond (thermal conductivity at room temperature can reach 2000W/m.K), Ra <2nm, contributing to a brand new application of AlN.

What's more, we can supply high quality polycrystalline diamond wafer, diamond heat sink, GaN & Diamond wafer and AlN on various substrate like Si, Sapphire and Diamond etc.