Longwave Plasmonics on Doped Silicon and Silicides

The realization of plasmo-electronic integrated circuits in a silicon chip will be enabled by two new plasmonic materials that are proposed and modeled in this article. The first is ion-implanted Si (n-type or p-type) at the surface of an intrinsic Si chip. The second is a thin-layer silicide such as Pd(2)Si, NiSi, PtSi(2) WSi(2) or CoSi(2) formed at the Si chip surface. For doping concentrations of 10(20) cm(-3) and 10(21) cm(-3), our dispersion calculations show that bound surface plasmon polaritons will propagate with low loss on stripe-shaped plasmonic waveguides over the 10 to 55 microm and 2.8 to 15 microm wavelength ranges, respectively. For Pd(2)Si/Si plasmonic waveguides, the wavelength range of 0.5 to 7.5 microm is useful and here the propagation lengths are 1 to 2300 microm. For both doped and silicided guides, the SPP mode field extends much more into the air above the stripe than it does into the conductive stripe material.