The de properties of silicon double drift region Impatt diodes for the low-high-low (n++nn+npp+pp++) structures have been optimized first by varying the high bias current density and then further by modifying the doping concentrations for the minimization of avalanche region width, punch through factor and optimization of power in the 80-150 GHz band. The computed results show that narrow avalanche region, minimum space charge effect and high efficiency diodes can be fabricated using appropriate doping profile at an optimum current density rather than increasing the bias current density which causes the space charge effect.