Suppression of parasitic surface conduction in Au-compensated high resistivity silicon for 40-GHz RF-MMIC application

Conductor-backed coplanar waveguides and meander inductors were fabricated on high resistivity 100 kΩ-cm Czochralski silicon substrates, created using a deep level doping compensation method. Attenuation measurement shows a large reduction in loss compared to reference Float-zone substrates. The loss is independent of applied bias voltages in the range of +6V (accumulation) to −6V (strong inversion) with a constant attenuation value of 0.2 dB/mm at 40 GHz. This indicates full suppression of bias-dependent parasitic surface conduction at the oxide-silicon interface. This conclusion is further supported by high frequency capacitance-voltage response obtained throughout the accumulation, depletion and inversion regions.