β-Ga2O3: ultralow-loss and low-permittivity dielectric ceramic for high-frequency packaging substrate

As the core carrier of integrated circuits, packaging substrates usually respond in time to the evolution of electronic products. Among which, ceramic substrate materials are desired to have excellent dielectric and voltage-resistant properties, high reliability, and good thermal and chemical stability. The beta-Ga2O3 ceramic prepared in this work has excellent microwave dielectric properties with a Q x f value of similar to 133 140 GHz (Q = 1/tan delta), epsilon(r) of similar to 9.57, and temperature coefficient of resonant frequency (TCF) value of similar to-58.2 ppm degrees C-1, which meet the requirements of high-frequency packages. Another highlight is that the beta-Ga2O3 ceramic has a higher dielectric strength of similar to 30 kV mm(-1) compared with conventional ceramic substrates, such as Al2O3, AlN, etc., allowing it to be used in higher-power circuits. Meanwhile, a flexural strength of similar to 110 MPa, a thermal expansion of similar to+8.9 ppm degrees C-1 and a thermal conductivity of similar to 15 W m(-1) K-1 have been achieved in the beta-Ga2O3 ceramic. In addition, a patch antenna for sub-6 GHz applications was designed and fabricated using the Ga2O3 ceramic substrate, showing good performance with a wide bandwidth of similar to 140 MHz, a return loss S-11 of similar to-21 dB at the center frequency, a radiation efficiency of similar to 92% and a gain of similar to 5 dBi. The stated results guarantee that the Ga2O3 ceramic shows great potential in applications towards high-frequency and high-power fields.