A structure for a semiconductor device includes an isolated MOSFET (e.g., NFET) having triple-well technology adjacent to an isolated PFET which itself is adjacent to an isolated NFET. The structure includes a substrate in which is formed a deep n-band region underneath any n-wells, p-wells and p-band regions within the substrate. One p-band region is formed above the deep n-band region and underneath the isolated p-well for the isolated MOSFET, while another p-band region is formed above the deep n-band region and underneath all of the p-wells and n-wells, including those that are part of the isolated PFET and NFET devices within the substrate. The n-wells for the isolated MOSFET are connected to the deep n-band region. The resulting structure provides for improved device isolation and reduction of noise propagating from the substrate to the FETs while maintaining the standard CMOS spacing layout spacing rules and electrical biasing characteristics both external and internal to the triple-well isolation regions.