Lateral discrete power MOSFET: enabling technology for next-generation, MHz-frequency, high-density DC/DC converters

Abstract

DC/DC converters to power future CPU or DSP cores mandate low-voltage power MOSFETs with ultra low on-resistance and gate charge. Conventional trench MOSFETs cannot meet the challenge. We introduce an alternative device technology, the discrete lateral power MOSFETs, to overcome the limitations associated with the vertical trench or planar MOSFETs. We report a family of 7V, 20V, and 30V lateral discrete power MOSFETs with figures of merit 2-3 times better than the state-of-the-art trench MOSFETs. We have developed an innovative metal interconnect and chip-scale packaging approach to overcome the scaling barrier which limits the chip size and current rating of the traditional lateral power devices. The lateral MOSFETs were designed and fabricated with a simplified CMOS process, and packaged in flip-chip forms using a wafer bumping technology. Lateral discrete power MOSFETs will become a viable enabling technology for next-generation, MHz-frequency, high-density DC/DC converters.