Design and Fabrication of Hyperabrupt Varactor Diode on GaAs substrate

In this paper, we have designed and fabricated hyperabrupt varactor diodes. Capacitance variations of hyperabrupt-doped varactor diodes are larger than those of uniform-doped varactor diodes. We adopted sensitivity S for the design of the hyperabrupt varactor diodes. The large S means the larger capacitance variations with biasing voltages. The measured reverse breakdown voltage of the fabricated varactor diodes was about 20 V. Also, the leakage current was 13 ㎁ at 20 V of reverse bias. The ideality factor was 1.15 at 300 K. For the anode contact diameter of 50 ㎛, the maximum capacitance of the fabricated varactor diode was 2.1 pF and the minimum capacitance 0.44 ㎊. Therefore, the C max /C min ratio was 4.77. Also, for the anode contact diameter of 60 ㎛, the maximum and minimum capacitances were 2.9 and 0.62 ㎊, respectively. And, thus, the C max /C min ratio was 4.64. The sensitivity of the fabricated varactor diodes (D=60 ㎛) was 2.37.