Zinc oxide thin films deposited on glass substrate at 150 °C by atomic layer deposition were annealed by the microwave method at temperatures below 500 °C. The microwave annealing effects on the structural and luminescent properties of ZnO films have been investigated by X-ray diffraction and photoluminescence. The results show that the MWA process can increase the crystal quality of ZnO thin films with a lower annealing temperature than RTA and relatively decrease the green luminescence of ZnO films. The observed changes have demonstrated that MWA is a viable technique for improving the crystalline quality of ZnO thin film on glass.

A novel shielding scheme is developed by inserting a concave shield between a metal–insulator–metal (MIM) capacitor and the silicon substrate. Chip measurements reveal that the concave shield improves the quality factor by 11% at 11.8 GHz and 14% at 18.8 GHz compared with an unshielded MIM capacitor. It also alleviates the effect on shunt capacitance between the bottom plate of the MIM capacitor and the shield layer. Moreover, because the concave shields simplify substrate modeling, a simple circuit model of the MIM capacitor with concave shield is presented for radio frequency applications.