Characteristics of GaAs varactor diode with hyperabrupt doping profile

We investigate the performance of hyperabrupt doping profile based GaAs varactor diodes. Epitaxially grown GaAs nn⁺ devices, having an intentionally graded n-active layer doping concentration, exhibit significant improvements in the breakdown voltage and capacitance relative to flat n-active layer devices. It is found that the varactor diodes with a hyperabrupt doping profile are effective in shifting the breakdown voltage. Moreover, the capacitance in the hyperabrupt graded junction is comparatively more dependent on the reverse-bias voltage than that in the uniformly doped junction. Experimental results indicate a maximum reverse breakdown voltage of 40 V at a leakage current of 165 μA. Furthermore, the maximum and minimum capacitances are 3.88 and 0.72 pF, respectively, for an anode diameter of 70 μm, resulting in a C_max/C_min ratio of 5.39.