Characteristics of GaAs varactor diode with hyperabrupt doping profile

Abstract

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 Cmax/Cmin ratio of 5.39. Packaged GaAs varactor diode for VCO applications.