Effect of charge bump on the series resistance and microwave properties of Si <i style="">n</i>⁺<i style="">np</i>⁺ IMPATT diode at X-band

Abstract

The value of series resistance (<i style="">R</i>_s) of Si <i style="">n</i>⁺<i style="">np</i>⁺ IMPATT diode has been studied through computer simulation considering experimental bias current and frequency in the X-band, and the results fit well with the device data (1.6 Ω at 10 GHz) for the flat doping profile. It is further observed that the value of <i style="">R</i>_s decreases from 1.76 to 0.1128 Ω at 10.7 GHz under experimental current density (3.45<img src='/image/spc_char/cross.gif' border=0>10⁶ A.m^-2) and temperature (373K), as the doping profile changes from flat to low-high-low(lhl) type with the incorporation of charge bump. The electric field and the negative resistivity profiles in the depletion layer clearly indicate the advantage of lhl doping profile on the series resistance as well as on its microwave properties. The analysis also gives an idea on the unison of load conductance of the waveguide and negative conductance of the diode at resonance.