Improved CMOS field isolation using germanium/boron implantation

A novel germanium/boron implantation technique for improving the electrical field isolation of high-density CMOS circuits is demonstrated. Germanium implantation causes a reduction in dopant diffusion and segregation during field oxidation and is shown to increase the p-well field threshold voltage by as much as 40% with no significant degradation to junction or device performance. Selective germanium implantation with a blanket boron field implant can also improve the electrical field isolation behavior for CMOS circuits.<>