The plasmonic property of heavily doped p-type silicon is studied here. Although most of the plasmonic devices use metal–insulator–metal (MIM) waveguide in order to support the propagation of surface plasmon polaritons (SPPs), metals that possess a number of challenges in loss management, polarization response, nanofabrication etc. On the other hand, heavily doped p-type silicon shows similar plasmonic properties like metals and also enables us to overcome the challenges possessed by metals. For numerical simulation, heavily doped p-silicon is mathematically modeled and the theoretically obtained relative permittivity is compared with the experimental value. A waveguide is formed with the p-silicon-air interface instead of the metal–air interface. Formation and propagation of SPPs similar to MIM waveguides are observed.