Micro-inductors integrated on silicon for power supply on chip

This paper discusses the technologies required to produce magnetics on silicon for power supply on chip. Prototypes of micro-inductors have been fabricated using techniques such as thick copper coil deposition and improved magnetic materials. The measured maximum Q factor and inductance value are 5 at 2.5 MHz and 38 nH/mm², respectively. The impact of seed layers and core overlap has been identified to be significant at high frequencies. Using the validated analytical model, the electrical performance of micro-inductors in a buck converter can be predicted and efficiency of 85.9 with a power density of 15.8 W/cm² can be achieved.