Ultrahigh-density trench capacitors in silicon and their application to integrated DC-DC conversion

This paper addresses silicon-based integration of passive components applied to 3D integration with dies of other technologies within one package. Particularly, the development of high-density trench capacitors has enabled the realization of small-formfactor DC-DC converters. As illustration, an integrated inductive DC-DC converter based on flip-chipping a 65-nm CMOS active die on a PICSÔ (Passive-Integration Connecting Substrate) passive die is described. The PICS die includes high-density (80 nF/mm2) integrated MOS trench capacitors. A converter peak efficiency of 87.5% is achieved at Vin=1.2 V, Vout=0.95 V, Iout=100 mA and 100-MHz switching frequency. The concept enables further integration with sensors, actuators and MEMS.