Design Consideration of a 3D Stacked Power Supply on Chip

In recent years, miniaturization and thinning of the power supply are attracted attentions. In this paper, we discuss the structure for the on-chip inductor and assembly technology suitable for 3D power SoC, which stacks GaN power device, passive devices, control circuit, and driver, based on wafer direct bonding technology and clarified the potential of the high frequency switching applications. We also propose the optimum structure and technology according to the switching frequency based on simulations.